Annotation of html5/workers/Overview.html, revision 1.273
1.271 ihickson 1: <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN"><!-- when publishing, change bits marked ZZZ
2: ZZZ: Set PUB to 1 for TR/ drafts, 0 for dev drafts; PUB-Y lines are used if it's 1 and PUB-N lines if it's 0.
3: ZZZ: Set YEAR, SHORTDAY (month/day), and LONGDAY accordingly. They are used by the INSERT FOO bits below.
4: --><html lang="en-US-x-Hixie"><title>Web Workers</title><style type="text/css">
1.82 ihickson 5: pre { margin-left: 2em; white-space: pre-wrap; }
6: h2 { margin: 3em 0 1em 0; }
7: h3 { margin: 2.5em 0 1em 0; }
8: h4 { margin: 2.5em 0 0.75em 0; }
9: h5, h6 { margin: 2.5em 0 1em; }
10: h1 + h2, h1 + h2 + h2 { margin: 0.75em 0 0.75em; }
11: h2 + h3, h3 + h4, h4 + h5, h5 + h6 { margin-top: 0.5em; }
12: p { margin: 1em 0; }
13: hr:not(.top) { display: block; background: none; border: none; padding: 0; margin: 2em 0; height: auto; }
14: dl, dd { margin-top: 0; margin-bottom: 0; }
15: dt { margin-top: 0.75em; margin-bottom: 0.25em; clear: left; }
16: dt + dt { margin-top: 0; }
17: dd dt { margin-top: 0.25em; margin-bottom: 0; }
18: dd p { margin-top: 0; }
19: dd dl + p { margin-top: 1em; }
20: dd table + p { margin-top: 1em; }
21: p + * > li, dd li { margin: 1em 0; }
22: dt, dfn { font-weight: bold; font-style: normal; }
23: dt dfn { font-style: italic; }
24: pre, code { font-size: inherit; font-family: monospace; font-variant: normal; }
25: pre strong { color: black; font: inherit; font-weight: bold; background: yellow; }
26: pre em { font-weight: bolder; font-style: normal; }
1.89 ihickson 27: @media screen { code { color: orangered; } code :link, code :visited { color: inherit; } }
1.82 ihickson 28: var sub { vertical-align: bottom; font-size: smaller; position: relative; top: 0.1em; }
29: table { border-collapse: collapse; border-style: hidden hidden none hidden; }
1.249 ihickson 30: table thead, table tbody { border-bottom: solid; }
1.82 ihickson 31: table tbody th:first-child { border-left: solid; }
1.180 ihickson 32: table tbody th { text-align: left; }
1.82 ihickson 33: table td, table th { border-left: solid; border-right: solid; border-bottom: solid thin; vertical-align: top; padding: 0.2em; }
34: blockquote { margin: 0 0 0 2em; border: 0; padding: 0; font-style: italic; }
35:
36: .bad, .bad *:not(.XXX) { color: gray; border-color: gray; background: transparent; }
37: .matrix, .matrix td { border: none; text-align: right; }
38: .matrix { margin-left: 2em; }
39: .dice-example { border-collapse: collapse; border-style: hidden solid solid hidden; border-width: thin; margin-left: 3em; }
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41: .dice-example td, .dice-example th { border: solid thin; width: 1.35em; height: 1.05em; text-align: center; padding: 0; }
42:
43: .toc dfn, h1 dfn, h2 dfn, h3 dfn, h4 dfn, h5 dfn, h6 dfn { font: inherit; }
44: img.extra { float: right; }
45: pre.idl { border: solid thin; background: #EEEEEE; color: black; padding: 0.5em 1em; }
46: pre.idl :link, pre.idl :visited { color: inherit; background: transparent; }
47: pre.css { border: solid thin; background: #FFFFEE; color: black; padding: 0.5em 1em; }
48: pre.css:first-line { color: #AAAA50; }
1.231 ihickson 49: dl.domintro { color: green; margin: 2em 0 2em 2em; padding: 0.5em 1em; border: none; background: #DDFFDD; }
1.82 ihickson 50: hr + dl.domintro, div.impl + dl.domintro { margin-top: 2.5em; margin-bottom: 1.5em; }
51: dl.domintro dt, dl.domintro dt * { color: black; text-decoration: none; }
52: dl.domintro dd { margin: 0.5em 0 1em 2em; padding: 0; }
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54: dl.switch { padding-left: 2em; }
55: dl.switch > dt { text-indent: -1.5em; }
56: dl.switch > dt:before { content: '\21AA'; padding: 0 0.5em 0 0; display: inline-block; width: 1em; text-align: right; line-height: 0.5em; }
1.121 ihickson 57: dl.triple { padding: 0 0 0 1em; }
58: dl.triple dt, dl.triple dd { margin: 0; display: inline }
59: dl.triple dt:after { content: ':'; }
60: dl.triple dd:after { content: '\A'; white-space: pre; }
1.82 ihickson 61: .diff-old { text-decoration: line-through; color: silver; background: transparent; }
62: .diff-chg, .diff-new { text-decoration: underline; color: green; background: transparent; }
63: a .diff-new { border-bottom: 1px blue solid; }
64:
65: h2 { page-break-before: always; }
1.139 ihickson 66: h1, h2, h3, h4, h5, h6 { page-break-after: avoid; }
1.82 ihickson 67: h1 + h2, hr + h2.no-toc { page-break-before: auto; }
68:
1.267 ihickson 69: p > span:not([title=""]):not([class="XXX"]):not([class="impl"]):not([class="note"]),
70: li > span:not([title=""]):not([class="XXX"]):not([class="impl"]):not([class="note"]), { border-bottom: solid #9999CC; }
1.82 ihickson 71:
72: div.head { margin: 0 0 1em; padding: 1em 0 0 0; }
73: div.head p { margin: 0; }
74: div.head h1 { margin: 0; }
75: div.head .logo { float: right; margin: 0 1em; }
76: div.head .logo img { border: none } /* remove border from top image */
77: div.head dl { margin: 1em 0; }
1.212 ihickson 78: div.head p.copyright, div.head p.alt { font-size: x-small; font-style: oblique; margin: 0; }
1.82 ihickson 79:
80: body > .toc > li { margin-top: 1em; margin-bottom: 1em; }
81: body > .toc.brief > li { margin-top: 0.35em; margin-bottom: 0.35em; }
82: body > .toc > li > * { margin-bottom: 0.5em; }
83: body > .toc > li > * > li > * { margin-bottom: 0.25em; }
84: .toc, .toc li { list-style: none; }
85:
86: .brief { margin-top: 1em; margin-bottom: 1em; line-height: 1.1; }
87: .brief li { margin: 0; padding: 0; }
88: .brief li p { margin: 0; padding: 0; }
89:
1.137 ihickson 90: .category-list { margin-top: -0.75em; margin-bottom: 1em; line-height: 1.5; }
91: .category-list::before { content: '\21D2\A0'; font-size: 1.2em; font-weight: 900; }
92: .category-list li { display: inline; }
93: .category-list li:not(:last-child)::after { content: ', '; }
94: .category-list li > span, .category-list li > a { text-transform: lowercase; }
95: .category-list li * { text-transform: none; } /* don't affect <code> nested in <a> */
96:
1.82 ihickson 97: .XXX { color: #E50000; background: white; border: solid red; padding: 0.5em; margin: 1em 0; }
98: .XXX > :first-child { margin-top: 0; }
99: p .XXX { line-height: 3em; }
1.158 ihickson 100: .annotation { border: solid thin black; background: #0C479D; color: white; position: relative; margin: 8px 0 20px 0; }
101: .annotation:before { position: absolute; left: 0; top: 0; width: 100%; height: 100%; margin: 6px -6px -6px 6px; background: #333333; z-index: -1; content: ''; }
102: .annotation :link, .annotation :visited { color: inherit; }
103: .annotation :link:hover, .annotation :visited:hover { background: transparent; }
104: .annotation span { border: none ! important; }
1.82 ihickson 105: .note { color: green; background: transparent; font-family: sans-serif; }
106: .warning { color: red; background: transparent; }
107: .note, .warning { font-weight: bolder; font-style: italic; }
108: p.note, div.note { padding: 0.5em 2em; }
109: span.note { padding: 0 2em; }
110: .note p:first-child, .warning p:first-child { margin-top: 0; }
111: .note p:last-child, .warning p:last-child { margin-bottom: 0; }
112: .warning:before { font-style: normal; }
113: p.note:before { content: 'Note: '; }
114: p.warning:before { content: '\26A0 Warning! '; }
115:
116: .bookkeeping:before { display: block; content: 'Bookkeeping details'; font-weight: bolder; font-style: italic; }
117: .bookkeeping { font-size: 0.8em; margin: 2em 0; }
118: .bookkeeping p { margin: 0.5em 2em; display: list-item; list-style: square; }
1.262 ihickson 119: .bookkeeping dt { margin: 0.5em 2em 0; }
120: .bookkeeping dd { margin: 0 3em 0.5em; }
1.82 ihickson 121:
122: h4 { position: relative; z-index: 3; }
123: h4 + .element, h4 + div + .element { margin-top: -2.5em; padding-top: 2em; }
124: .element {
1.88 ihickson 125: background: #EEEEFF;
1.82 ihickson 126: color: black;
127: margin: 0 0 1em 0.15em;
128: padding: 0 1em 0.25em 0.75em;
1.88 ihickson 129: border-left: solid #9999FF 0.25em;
1.82 ihickson 130: position: relative;
131: z-index: 1;
132: }
133: .element:before {
134: position: absolute;
135: z-index: 2;
136: top: 0;
137: left: -1.15em;
138: height: 2em;
139: width: 0.9em;
1.88 ihickson 140: background: #EEEEFF;
1.82 ihickson 141: content: ' ';
142: border-style: none none solid solid;
1.88 ihickson 143: border-color: #9999FF;
1.82 ihickson 144: border-width: 0.25em;
145: }
146:
1.156 ihickson 147: .example { display: block; color: #222222; background: #FCFCFC; border-left: double; margin-left: 2em; padding-left: 1em; }
148: td > .example:only-child { margin: 0 0 0 0.1em; }
1.82 ihickson 149:
1.131 ihickson 150: ul.domTree, ul.domTree ul { padding: 0 0 0 1em; margin: 0; }
151: ul.domTree li { padding: 0; margin: 0; list-style: none; position: relative; }
152: ul.domTree li li { list-style: none; }
153: ul.domTree li:first-child::before { position: absolute; top: 0; height: 0.6em; left: -0.75em; width: 0.5em; border-style: none none solid solid; content: ''; border-width: 0.1em; }
154: ul.domTree li:not(:last-child)::after { position: absolute; top: 0; bottom: -0.6em; left: -0.75em; width: 0.5em; border-style: none none solid solid; content: ''; border-width: 0.1em; }
155: ul.domTree span { font-style: italic; font-family: serif; }
156: ul.domTree .t1 code { color: purple; font-weight: bold; }
157: ul.domTree .t2 { font-style: normal; font-family: monospace; }
158: ul.domTree .t2 .name { color: black; font-weight: bold; }
159: ul.domTree .t2 .value { color: blue; font-weight: normal; }
160: ul.domTree .t3 code, .domTree .t4 code, .domTree .t5 code { color: gray; }
161: ul.domTree .t7 code, .domTree .t8 code { color: green; }
162: ul.domTree .t10 code { color: teal; }
163:
1.225 ihickson 164: body.dfnEnabled dfn { cursor: pointer; }
165: .dfnPanel {
166: display: inline;
167: position: absolute;
168: z-index: 10;
169: height: auto;
170: width: auto;
171: padding: 0.5em 0.75em;
172: font: small sans-serif, Droid Sans Fallback;
173: background: #DDDDDD;
174: color: black;
175: border: outset 0.2em;
176: }
177: .dfnPanel * { margin: 0; padding: 0; font: inherit; text-indent: 0; }
178: .dfnPanel :link, .dfnPanel :visited { color: black; }
179: .dfnPanel p { font-weight: bolder; }
180: .dfnPanel * + p { margin-top: 0.25em; }
181: .dfnPanel li { list-style-position: inside; }
182:
1.207 ihickson 183: #configUI { position: absolute; z-index: 20; top: 10em; right: 1em; width: 11em; font-size: small; }
184: #configUI p { margin: 0.5em 0; padding: 0.3em; background: #EEEEEE; color: black; border: inset thin; }
185: #configUI p label { display: block; }
186: #configUI #updateUI, #configUI .loginUI { text-align: center; }
187: #configUI input[type=button] { display: block; margin: auto; }
1.260 ihickson 188:
1.268 ihickson 189: fieldset { margin: 1em; padding: 0.5em 1em; }
190: fieldset > legend + * { margin-top: 0; }
1.266 ihickson 191: fieldset > :last-child { margin-bottom: 0; }
1.268 ihickson 192: fieldset p { margin: 0.5em 0; }
1.266 ihickson 193:
1.271 ihickson 194: </style><link href="http://www.w3.org/StyleSheets/TR/W3C-ED" rel="stylesheet" type="text/css"><script type="text/javascript">
195: function getCookie(name) {
196: var params = location.search.substr(1).split("&");
197: for (var index = 0; index < params.length; index++) {
198: if (params[index] == name)
199: return "1";
200: var data = params[index].split("=");
201: if (data[0] == name)
202: return unescape(data[1]);
203: }
204: var cookies = document.cookie.split("; ");
205: for (var index = 0; index < cookies.length; index++) {
206: var data = cookies[index].split("=");
207: if (data[0] == name)
208: return unescape(data[1]);
209: }
210: return null;
211: }
212: function load(script) {
213: var e = document.createElement('script');
214: e.setAttribute('src', 'http://www.whatwg.org/specs/web-apps/current-work/' + script + '?' + encodeURIComponent(location) + '&' + encodeURIComponent(document.referrer));
215: document.body.appendChild(e);
216: }
217: function init() {
218: if (location.search == '?slow-browser')
219: return;
220: var configUI = document.createElement('div');
221: configUI.id = 'configUI';
222: document.body.appendChild(configUI);
223: load('dfn.js'); // doesn't support split-out specs, but, oh well.
224: if (getCookie('profile') == '1')
225: document.getElementsByTagName('h2')[0].textContent += '; load: ' + (new Date() - loadTimer) + 'ms';
226: fixBrokenLink();
227: }
228: </script><body onload="init()"><div class="head" id="head">
1.115 ihickson 229: <p><a href="http://www.w3.org/"><img alt="W3C" height="48" src="http://www.w3.org/Icons/w3c_home" width="72"></a></p>
1.271 ihickson 230:
1.54 ihickson 231: <h1>Web Workers</h1>
1.271 ihickson 232: <!--<h2 class="no-num no-toc">(subtitle)</h2>-->
1.273 ! ihickson 233: <h2 class="no-num no-toc" id="editor-s-draft-20-january-2011">Editor's Draft 20 January 2011</h2>
1.218 ihickson 234: <dl><dt>Latest Published Version:</dt>
1.115 ihickson 235: <dd><a href="http://www.w3.org/TR/workers/">http://www.w3.org/TR/workers/</a></dd>
1.109 ihickson 236: <dt>Latest Editor's Draft:</dt>
1.260 ihickson 237: <dd><a class="latest-link" href="http://dev.w3.org/html5/workers/">http://dev.w3.org/html5/workers/</a></dd>
1.117 ihickson 238: <!-- ZZZ: add the new version after it has shipped-->
1.2 ihickson 239: <dt>Previous Versions:</dt>
1.113 ihickson 240: <dd><a href="http://www.w3.org/TR/2009/WD-workers-20090423/">http://www.w3.org/TR/2009/WD-workers-20090423/</a>
1.198 ihickson 241: <dd><a href="http://www.w3.org/TR/2009/WD-workers-20091029/">http://www.w3.org/TR/2009/WD-workers-20091029/</a></dd>
1.117 ihickson 242: <!-- :ZZZ -->
1.271 ihickson 243: <dt>Editor:</dt>
1.115 ihickson 244: <dd><a href="mailto:ian@hixie.ch">Ian Hickson</a>, Google, Inc.</dd>
1.155 ihickson 245: </dl><p class="copyright"><a href="http://www.w3.org/Consortium/Legal/ipr-notice#Copyright">Copyright</a>
1.234 ihickson 246: © 2010 <a href="http://www.w3.org/"><abbr title="World Wide
1.155 ihickson 247: Web Consortium">W3C</abbr></a><sup>®</sup> (<a href="http://www.csail.mit.edu/"><abbr title="Massachusetts
1.115 ihickson 248: Institute of Technology">MIT</abbr></a>, <a href="http://www.ercim.org/"><abbr title="European Research
249: Consortium for Informatics and Mathematics">ERCIM</abbr></a>, <a href="http://www.keio.ac.jp/">Keio</a>), All Rights Reserved. W3C
250: <a href="http://www.w3.org/Consortium/Legal/ipr-notice#Legal_Disclaimer">liability</a>,
251: <a href="http://www.w3.org/Consortium/Legal/ipr-notice#W3C_Trademarks">trademark</a>
252: and <a href="http://www.w3.org/Consortium/Legal/copyright-documents">document
1.81 ihickson 253: use</a> rules apply.</p>
1.201 ihickson 254:
1.254 ihickson 255:
1.252 ihickson 256: <!-- UNDER NO CIRCUMSTANCES IS THE FOLLOWING PARAGRAPH TO BE REMOVED OR EDITED WITHOUT TALKING TO IAN FIRST -->
1.255 ihickson 257: <p class="alt">The bulk of the text of this specification is also
1.254 ihickson 258: available in the WHATWG <a href="http://www.whatwg.org/specs/web-apps/current-work/complete.html#workers">Web Applications 1.0</a> specification, under a license that permits
259: reuse of the specification text.</p>
1.252 ihickson 260: <!-- UNDER NO CIRCUMSTANCES IS THE PRECEDING PARAGRAPH TO BE REMOVED OR EDITED WITHOUT TALKING TO IAN FIRST -->
261:
1.254 ihickson 262:
1.155 ihickson 263: </div><hr class="top"><h2 class="no-num no-toc" id="abstract">Abstract</h2><p>This specification defines an API that allows Web application
1.81 ihickson 264: authors to spawn background workers running scripts in parallel to
265: their main page. This allows for thread-like operation with
1.212 ihickson 266: message-passing as the coordination mechanism.<h2 class="no-num no-toc" id="status-of-this-document">Status of This document</h2><!-- intro boilerplate (required) --><p><em>This section describes the status of this document at the
1.81 ihickson 267: time of its publication. Other documents may supersede this
268: document. A list of current W3C publications and the most recently
269: formally published revision of this technical report can be found in
1.115 ihickson 270: the <a href="http://www.w3.org/TR/">W3C technical reports index</a>
1.271 ihickson 271: at http://www.w3.org/TR/.</em></p><!-- where to send feedback (required) --><p>If you wish to make comments regarding this document in a manner
272: that is tracked by the W3C, please submit them via using <a href="http://www.w3.org/Bugs/Public/enter_bug.cgi?product=HTML%20WG">our
273: public bug database</a>. If you do not have an account then you can
274: enter feedback using this form:<form action="http://www.whatwg.org/specs/web-apps/current-work/file-spam.cgi" method="post">
275: <fieldset><legend>Feedback Comments</legend>
276: <input name="id" type="hidden" value="top"><input name="component" type="hidden" value="Web Workers (editor: Ian Hickson)"><input name="response" type="hidden" value="html"><p><label for="feedbackBox">Please enter your feedback, carefully
277: indicating the title of the section for which you are submitting
278: feedback, quoting the text that's wrong today if appropriate. If
279: you're suggesting a new feature, it's really important to say
280: <em>what</em> the problem you're trying to solve is. That's more
281: important than the solution, in fact.</label></p>
282: <p><textarea cols="79" id="feedbackBox" name="text" rows="10"></textarea></p>
283: <p class="note">Please don't use section numbers as these tend to
284: change rapidly and make your feedback harder to understand.</p>
285: <script type="text/javascript">
286: function checkFeedbackForm(form) {
287: if (form.elements.text.value.match(/ [^ ]+ [^ ]+ [^ ]+ [^ ]+ /)) {
288: form.action = "http://www.whatwg.org/specs/web-apps/current-work/file-bug.cgi";
289: return true;
290: } else {
291: alert('Please include significantly more detail about exactly what problem you are trying to solve.');
292: return false;
293: }
294: }
295: </script><p>
296: <input onclick="return checkFeedbackForm(form)" type="submit" value="Submit feedback"><small>(Note: Your IP address will be publicly recorded for spam prevention purposes.)</small>
297: </p>
298: </fieldset></form><p>You can also e-mail feedback to <a href="mailto:public-webapps@w3.org">public-webapps@w3.org</a> (<a href="mailto:public-webapps-request@w3.org?subject=subscribe">subscribe</a>,
299: <a href="http://lists.w3.org/Archives/Public/public-webapps/">archives</a>),
1.115 ihickson 300: or <a href="mailto:whatwg@whatwg.org">whatwg@whatwg.org</a> (<a href="http://lists.whatwg.org/listinfo.cgi/whatwg-whatwg.org">subscribe</a>,
301: <a href="http://lists.whatwg.org/pipermail/whatwg-whatwg.org/">archives</a>).
1.155 ihickson 302: All feedback is welcome.</p><!-- stability (required) --><p>Implementors should be aware that this specification is not
1.81 ihickson 303: stable. <strong>Implementors who are not taking part in the
304: discussions are likely to find the specification changing out from
305: under them in incompatible ways.</strong> Vendors interested in
306: implementing this specification before it eventually reaches the
307: Candidate Recommendation stage should join the aforementioned
1.271 ihickson 308: mailing lists and take part in the discussions.<div id="multipage-common">
309: </div><!-- version history or list of changes (required) --><p>The latest
310: stable version of the editor's draft of this specification is always
311: available on <a href="http://dev.w3.org/html5/workers/">the W3C CVS server</a>
312: and in the <a href="http://svn.whatwg.org/webapps/">WHATWG
313: Subversion repository</a>. The <a href="http://www.whatwg.org/specs/web-apps/current-work/complete.html">latest
314: editor's working copy</a> (which may contain unfinished text in the
315: process of being prepared) contains the latest draft text of this
316: specification (amongst others). For more details, please see the <a href="http://wiki.whatwg.org/wiki/FAQ#What_are_the_various_versions_of_the_spec.3F">WHATWG
317: FAQ</a>.<p>Notifications of changes to this specification are sent along
318: with notifications of changes to related specifications using the
319: following mechanisms:<dl><dt>E-mail notifications of changes</dt>
320: <dd>Commit-Watchers mailing list (complete source diffs): <a href="http://lists.whatwg.org/listinfo.cgi/commit-watchers-whatwg.org">http://lists.whatwg.org/listinfo.cgi/commit-watchers-whatwg.org</a></dd>
321: <dt>Browsable version-control record of all changes:</dt>
322: <dd>CVSWeb interface with side-by-side diffs: <a href="http://dev.w3.org/cvsweb/html5/">http://dev.w3.org/cvsweb/html5/</a></dd>
323: <dd>Annotated summary with unified diffs: <a href="http://html5.org/tools/web-apps-tracker">http://html5.org/tools/web-apps-tracker</a></dd>
324: <dd>Raw Subversion interface: <code>svn checkout http://svn.whatwg.org/webapps/</code></dd>
325: </dl><p>The W3C <a href="http://www.w3.org/2008/webapps/">Web Applications
1.81 ihickson 326: Working Group</a> is the W3C working group responsible for this
327: specification's progress along the W3C Recommendation track.
1.273 ! ihickson 328: This specification is the 20 January 2011 Editor's Draft.
1.271 ihickson 329: </p><!-- required patent boilerplate --><p>This document was produced by a group operating under the <a href="http://www.w3.org/Consortium/Patent-Policy-20040205/">5
1.115 ihickson 330: February 2004 W3C Patent Policy</a>. W3C maintains a <a href="http://www.w3.org/2004/01/pp-impl/42538/status" rel="disclosure">public list of
1.81 ihickson 331: any patent disclosures</a> made in connection with the deliverables
332: of the group; that page also includes instructions for disclosing a
333: patent. An individual who has actual knowledge of a patent which the
1.115 ihickson 334: individual believes contains <a href="http://www.w3.org/Consortium/Patent-Policy-20040205/#def-essential">Essential
335: Claim(s)</a> must disclose the information in accordance with <a href="http://www.w3.org/Consortium/Patent-Policy-20040205/#sec-Disclosure">section
1.252 ihickson 336: 6 of the W3C Patent Policy</a>.<h2 class="no-num no-toc" id="contents">Table of Contents</h2>
1.81 ihickson 337: <!--begin-toc-->
1.115 ihickson 338: <ol class="toc">
339: <li><a href="#introduction"><span class="secno">1 </span>Introduction</a>
1.81 ihickson 340: <ol>
1.115 ihickson 341: <li><a href="#scope"><span class="secno">1.1 </span>Scope</a></li>
342: <li><a href="#tutorial"><span class="secno">1.2 </span>Tutorial</a>
1.81 ihickson 343: <ol>
1.115 ihickson 344: <li><a href="#a-background-number-crunching-worker"><span class="secno">1.2.1 </span>A background number-crunching worker</a></li>
345: <li><a href="#a-worker-for-updating-a-client-side-database"><span class="secno">1.2.2 </span>A worker for updating a client-side database</a></li>
346: <li><a href="#worker-used-for-background-i-o"><span class="secno">1.2.3 </span>Worker used for background I/O</a></li>
1.238 ihickson 347: <li><a href="#shared-workers-introduction"><span class="secno">1.2.4 </span>Shared workers introduction</a></li>
348: <li><a href="#shared-state-using-a-shared-worker"><span class="secno">1.2.5 </span>Shared state using a shared worker</a></li>
349: <li><a href="#delegation"><span class="secno">1.2.6 </span>Delegation</a></li>
350: <li><a href="#providing-libraries"><span class="secno">1.2.7 </span>Providing libraries</a></ol></ol></li>
1.148 ihickson 351: <li><a href="#conformance-requirements"><span class="secno">2 </span>Conformance requirements</a>
1.82 ihickson 352: <ol>
1.148 ihickson 353: <li><a href="#dependencies"><span class="secno">2.1 </span>Dependencies</a></ol></li>
354: <li><a href="#terminology"><span class="secno">3 </span>Terminology</a></li>
355: <li><a href="#infrastructure"><span class="secno">4 </span>Infrastructure</a>
356: <ol>
357: <li><a href="#the-global-scope"><span class="secno">4.1 </span>The global scope</a>
1.81 ihickson 358: <ol>
1.148 ihickson 359: <li><a href="#the-workerglobalscope-abstract-interface"><span class="secno">4.1.1 </span>The <code>WorkerGlobalScope</code> abstract interface</a></li>
360: <li><a href="#dedicated-workers-and-the-dedicatedworkerglobalscope-interface"><span class="secno">4.1.2 </span>Dedicated workers and the <code>DedicatedWorkerGlobalScope</code> interface</a></li>
1.270 ihickson 361: <li><a href="#shared-workers-and-the-sharedworkerglobalscope-interface"><span class="secno">4.1.3 </span>Shared workers and the <code>SharedWorkerGlobalScope</code> interface</a></ol></li>
1.160 ihickson 362: <li><a href="#origins-of-workers"><span class="secno">4.2 </span>Origins of workers</a></li>
1.186 ihickson 363: <li><a href="#the-event-loop"><span class="secno">4.3 </span>The event loop</a></li>
364: <li><a href="#the-worker-s-lifetime"><span class="secno">4.4 </span>The worker's lifetime</a></li>
365: <li><a href="#processing-model"><span class="secno">4.5 </span>Processing model</a></li>
366: <li><a href="#runtime-script-errors"><span class="secno">4.6 </span>Runtime script errors</a></li>
367: <li><a href="#creating-workers"><span class="secno">4.7 </span>Creating workers</a>
1.81 ihickson 368: <ol>
1.186 ihickson 369: <li><a href="#the-abstractworker-abstract-interface"><span class="secno">4.7.1 </span>The <code>AbstractWorker</code> abstract interface</a></li>
370: <li><a href="#dedicated-workers-and-the-worker-interface"><span class="secno">4.7.2 </span>Dedicated workers and the <code>Worker</code> interface</a></li>
371: <li><a href="#shared-workers-and-the-sharedworker-interface"><span class="secno">4.7.3 </span>Shared workers and the <code>SharedWorker</code> interface</a></ol></ol></li>
1.148 ihickson 372: <li><a href="#apis-available-to-workers"><span class="secno">5 </span>APIs available to workers</a>
1.81 ihickson 373: <ol>
1.148 ihickson 374: <li><a href="#importing-scripts-and-libraries"><span class="secno">5.1 </span>Importing scripts and libraries</a></li>
1.210 ihickson 375: <li><a href="#the-workernavigator-object"><span class="secno">5.2 </span>The <code>WorkerNavigator</code> object</a></li>
1.272 ihickson 376: <li><a href="#interface-objects-and-constructors"><span class="secno">5.3 </span>Interface objects and constructors</a></li>
377: <li><a href="#worker-locations"><span class="secno">5.4 </span>Worker locations</a></ol></li>
1.115 ihickson 378: <li><a class="no-num" href="#references">References</a></li>
379: <li><a class="no-num" href="#acknowledgements">Acknowledgements</a></ol>
1.155 ihickson 380: <!--end-toc--><hr><h2 id="introduction"><span class="secno">1 </span>Introduction</h2><h3 id="scope"><span class="secno">1.1 </span>Scope</h3><p><i>This section is non-normative.</i><p>This specification defines an API for running scripts in the
381: background independently of any user interface scripts.<p>This allows for long-running scripts that are not interrupted by
1.81 ihickson 382: scripts that respond to clicks or other user interactions, and
383: allows long tasks to be executed without yielding to keep the page
1.155 ihickson 384: responsive.<p>Workers (as these background scripts are called herein) are
1.81 ihickson 385: relatively heavy-weight, and are not intended to be used in large
386: numbers. For example, it would be inappropriate to launch one worker
387: for each pixel of a four megapixel image. The examples below show
1.155 ihickson 388: some appropriate uses of workers.<p>Generally, workers are expected to be long-lived, have a high
389: start-up performance cost, and a high per-instance memory cost.<h3 id="tutorial"><span class="secno">1.2 </span>Tutorial</h3><p><i>This section is non-normative.</i><p>There are a variety of uses that workers can be put to. The
390: following subsections show various examples of this use.<h4 id="a-background-number-crunching-worker"><span class="secno">1.2.1 </span>A background number-crunching worker</h4><p><i>This section is non-normative.</i><p>The simplest use of workers is for performing a computationally
391: expensive task without interrupting the user interface.<p>In this example, the main document spawns a worker to
392: (naïvely) compute prime numbers, and progressively displays the
393: most recently found prime number.<p>The main page is as follows:<pre><!DOCTYPE HTML>
1.81 ihickson 394: <html>
395: <head>
396: <title>Worker example: One-core computation</title>
397: </head>
398: <body>
399: <p>The highest prime number discovered so far is: <output id="result"></output></p>
400: <script>
1.50 ihickson 401: var worker = new Worker('worker.js');
402: worker.onmessage = function (event) {
1.54 ihickson 403: document.getElementById('result').textContent = event.data;
1.29 ihickson 404: };
1.81 ihickson 405: </script>
406: </body>
1.155 ihickson 407: </html></pre><p>The <code title="dom-Worker"><a href="#dom-worker">Worker()</a></code> constructor call
1.115 ihickson 408: creates a worker and returns a <code><a href="#worker">Worker</a></code> object
1.81 ihickson 409: representing that worker, which is used to communicate with the
1.177 ihickson 410: worker. That object's <code title="handler-Worker-onmessage"><a href="#handler-worker-onmessage">onmessage</a></code> event handler allows the code to receive messages from the worker.<p>The worker itself is as follows:<pre>var n = 1;
1.29 ihickson 411: search: while (true) {
412: n += 1;
413: for (var i = 2; i <= Math.sqrt(n); i += 1)
414: if (n % i == 0)
415: continue search;
416: // found a prime!
1.50 ihickson 417: postMessage(n);
1.155 ihickson 418: }</pre><p>The bulk of this code is simply an unoptimized search for a prime
1.115 ihickson 419: number. To send a message back to the page, the <code title="dom-DedicatedWorkerGlobalScope-postMessage"><a href="#dom-dedicatedworkerglobalscope-postmessage">postMessage()</a></code>
1.155 ihickson 420: method is used to post a message when a prime is found.<p><a href="http://www.whatwg.org/demos/workers/primes/page.html">View this example online</a>.<h4 id="a-worker-for-updating-a-client-side-database"><span class="secno">1.2.2 </span>A worker for updating a client-side database</h4><p><i>This section is non-normative.</i><p>In this example, the main document spawns a worker whose only
1.81 ihickson 421: task is to listen for notifications from the server, and, when
422: appropriate, either add or remove data from the client-side
1.155 ihickson 423: database.<p>Since no communication occurs between the worker and the main
424: page, the main page can start the worker by just doing:<pre><script>
1.50 ihickson 425: new Worker('worker.js');
1.155 ihickson 426: </script></pre><p>The worker itself is as follows:<pre>var server = new WebSocket('ws://whatwg.org/database');
1.42 ihickson 427: var database = openDatabase('demobase', '1.0', 'Demo Database', 10240);
1.31 ihickson 428: server.onmessage = function (event) {
429: // data is in the format "command key value"
1.54 ihickson 430: var data = event.data.split(' ');
1.31 ihickson 431: switch (data[0]) {
432: case '+':
433: database.transaction(function(tx) {
434: tx.executeSql('INSERT INTO pairs (key, value) VALUES (?, ?)', data[1], data[2]);
435: });
436: case '-':
437: database.transaction(function(tx) {
438: tx.executeSql('DELETE FROM pairs WHERE key=? AND value=?', data[1], data[2]);
439: });
440: }
1.155 ihickson 441: };</pre><p>This connects to the server using the <code>WebSocket</code>
1.81 ihickson 442: mechanism and opens the local database (which, we presume, has been
443: created earlier). The worker then just listens for messages from the
444: server and acts on them as appropriate, forever (or until the main
1.155 ihickson 445: page is closed).<p><a href="http://www.whatwg.org/demos/workers/database-updater/page.html">View
1.81 ihickson 446: this example online</a>. (This example will not actually function,
447: since the server does not actually exist and the database is not
1.155 ihickson 448: created by this sample code.)<h4 id="worker-used-for-background-i-o"><span class="secno">1.2.3 </span>Worker used for background I/O</h4><p><i>This section is non-normative.</i><p>In this example, the main document uses two workers, one for
1.81 ihickson 449: fetching stock updates for at regular intervals, and one for
1.155 ihickson 450: fetching performing search queries that the user requests.<p>The main page is as follows:<pre><!DOCTYPE HTML>
1.81 ihickson 451: <html>
452: <head>
453: <title>Worker example: Stock ticker</title>
454: <script>
1.33 ihickson 455: // TICKER
456: var symbol = 'GOOG'; // default symbol to watch
1.50 ihickson 457: var ticker = new Worker('ticker.js');
1.33 ihickson 458:
459: // SEARCHER
1.50 ihickson 460: var searcher = new Worker('searcher.js');
1.33 ihickson 461: function search(query) {
1.50 ihickson 462: searcher.postMessage(query);
1.33 ihickson 463: }
464:
465: // SYMBOL SELECTION UI
466: function select(newSymbol) {
467: symbol = newSymbol;
1.50 ihickson 468: ticker.postMessage(symbol);
1.33 ihickson 469: }
1.81 ihickson 470: </script>
471: </head>
1.122 ihickson 472: <body onload="search('')">
1.81 ihickson 473: <p><output id="symbol"></output> <output id="value"></output></p>
474: <script>
1.50 ihickson 475: ticker.onmessage = function (event) {
1.54 ihickson 476: var data = event.data.split(' ');
1.33 ihickson 477: document.getElementById('symbol').textContent = data[0];
478: document.getElementById('value').textContent = data[1];
479: };
1.50 ihickson 480: ticker.postMessage(symbol);
1.81 ihickson 481: </script>
1.122 ihickson 482: <p><label>Search: <input type="text" autofocus oninput="search(this.value)"></label></p>
1.81 ihickson 483: <ul id="results"></ul>
484: <script>
1.50 ihickson 485: searcher.onmessage = function (event) {
1.54 ihickson 486: var data = event.data.split(' ');
1.33 ihickson 487: var results = document.getElementById('results');
488: while (results.hasChildNodes()) // clear previous results
489: results.removeChild(results.firstChild);
490: for (var i = 0; i < data.length; i += 1) {
491: // add a list item with a button for each result
492: var li = document.createElement('li');
493: var button = document.createElement('button');
494: button.value = data[i];
495: button.type = 'button';
496: button.onclick = function () { select(this.value); };
497: button.textContent = data[i];
498: li.appendChild(button);
499: results.appendChild(li);
500: }
501: };
1.81 ihickson 502: </script>
503: <p>(The data in this example is not real. Try searching for "Google" or "Apple".)</p>
504: </body>
1.155 ihickson 505: </html></pre><p>The two workers use a common library for performing the actual
506: network calls. This library is as follows:<pre>function get(url) {
1.50 ihickson 507: try {
508: var xhr = new XMLHttpRequest();
509: xhr.open('GET', url, false);
510: xhr.send();
511: return xhr.responseText;
512: } catch (e) {
513: return ''; // turn all errors into empty results
514: }
1.155 ihickson 515: }</pre><p>The stock updater worker is as follows:<pre>importScripts('io.js');
1.33 ihickson 516: var timer;
517: var symbol;
518: function update() {
1.50 ihickson 519: postMessage(symbol + ' ' + get('stock.cgi?' + symbol));
1.33 ihickson 520: timer = setTimeout(update, 10000);
521: }
1.50 ihickson 522: onmessage = function (event) {
1.33 ihickson 523: if (timer)
524: clearTimeout(timer);
1.54 ihickson 525: symbol = event.data;
1.33 ihickson 526: update();
1.155 ihickson 527: };</pre><p>The search query worker is as follows:<pre>importScripts('io.js');
1.50 ihickson 528: onmessage = function (event) {
1.54 ihickson 529: postMessage(get('search.cgi?' + event.data));
1.238 ihickson 530: };</pre><p><a href="http://www.whatwg.org/demos/workers/stocks/page.html">View this example online</a>.<h4 id="shared-workers-introduction"><span class="secno">1.2.4 </span>Shared workers introduction</h4><p><i>This section is non-normative.</i><p>This section introduces shared workers using a Hello World
531: example. Shared workers use slightly different APIs, since each
532: worker can have multiple connections.<p>This first example shows how you connect to a worker and how a
533: worker can send a message back to the page when it connects to
1.239 ihickson 534: it. Received messages are displayed in a log.<p>Here is the HTML page:<pre><!DOCTYPE HTML>
535: <title>Shared workers: demo 1</title>
536: <pre id="log">Log:</pre>
537: <script>
538: var worker = new SharedWorker('test.js');
539: var log = document.getElementById('log');
540: worker.port.onmessage = function(e) { // note: not worker.onmessage!
541: log.textContent += '\n' + e.data;
542: }
543: </script>
544: </pre><p>Here is the JavaScript worker:<pre>onconnect = function(e) {
545: var port = e.ports[0];
546: port.postMessage('Hello World!');
547: }
1.259 ihickson 548: </pre><p><a href="http://www.whatwg.org/demos/workers/shared/001/test.html">View this example online</a>.<hr><p>This second example extends the first one by changing two things:
1.238 ihickson 549: first, messages are received using <code title="">addEventListener()</code> instead of an <span title="event
550: handler IDL attributes">event handler IDL attribute</span>, and
551: second, a message is sent <em>to</em> the worker, causing the worker
552: to send another message in return. Received messages are again
1.239 ihickson 553: displayed in a log.<p>Here is the HTML page:<pre><!DOCTYPE HTML>
1.240 ihickson 554: <title>Shared workers: demo 2</title>
1.239 ihickson 555: <pre id="log">Log:</pre>
556: <script>
557: var worker = new SharedWorker('test.js');
558: var log = document.getElementById('log');
1.240 ihickson 559: worker.port.addEventListener('message', function(e) {
1.239 ihickson 560: log.textContent += '\n' + e.data;
1.240 ihickson 561: }, false);
562: worker.port.start(); // note: need this when using addEventListener
563: worker.port.postMessage('ping');
1.239 ihickson 564: </script>
565: </pre><p>Here is the JavaScript worker:<pre>onconnect = function(e) {
566: var port = e.ports[0];
567: port.postMessage('Hello World!');
1.240 ihickson 568: port.onmessage = function(e) {
569: port.postMessage('pong'); // not e.ports[0].postMessage!
570: // e.target.postMessage('pong'); would work also
571: }
1.239 ihickson 572: }
1.259 ihickson 573: </pre><p><a href="http://www.whatwg.org/demos/workers/shared/002/test.html">View this example online</a>.<hr><p>Finally, the example is extended to show how two pages can
1.238 ihickson 574: connect to the same worker; in this case, the second page is merely
575: in an <code>iframe</code> on the first page, but the same principle
576: would apply to an entirely separate page in a separate
1.239 ihickson 577: <span>top-level browsing context</span>.<p>Here is the outer HTML page:<pre><!DOCTYPE HTML>
578: <title>Shared workers: demo 3</title>
579: <pre id="log">Log:</pre>
580: <script>
581: var worker = new SharedWorker('test.js');
582: var log = document.getElementById('log');
583: worker.port.addEventListener('message', function(e) {
584: log.textContent += '\n' + e.data;
585: }, false);
586: worker.port.start();
587: worker.port.postMessage('ping');
588: </script>
589: <iframe src="inner.html"></iframe>
590: </pre><p>Here is the inner HTML page:<pre><!DOCTYPE HTML>
591: <title>Shared workers: demo 3 inner frame</title>
592: <pre id=log>Inner log:</pre>
593: <script>
594: var worker = new SharedWorker('test.js');
595: var log = document.getElementById('log');
596: worker.port.onmessage = function(e) {
597: log.textContent += '\n' + e.data;
598: }
599: </script>
600: </pre><p>Here is the JavaScript worker:<pre>var count = 0;
601: onconnect = function(e) {
602: count += 1;
603: var port = e.ports[0];
604: port.postMessage('Hello World! You are connection #' + count);
605: port.onmessage = function(e) {
606: port.postMessage('pong');
607: }
608: }
1.259 ihickson 609: </pre><p><a href="http://www.whatwg.org/demos/workers/shared/003/test.html">View this example online</a>.<h4 id="shared-state-using-a-shared-worker"><span class="secno">1.2.5 </span>Shared state using a shared worker</h4><p><i>This section is non-normative.</i><p>In this example, multiple windows (viewers) can be opened that
1.81 ihickson 610: are all viewing the same map. All the windows share the same map
611: information, with a single worker coordinating all the viewers. Each
612: viewer can move around independently, but if they set any data on
1.155 ihickson 613: the map, all the viewers are updated.<p>The main page isn't interesting, it merely provides a way to open
614: the viewers:<pre><!DOCTYPE HTML>
1.81 ihickson 615: <html>
616: <head>
617: <title>Workers example: Multiviewer</title>
618: <script>
1.36 ihickson 619: function openViewer() {
620: window.open('viewer.html');
621: }
1.81 ihickson 622: </script>
623: </head>
624: <body>
625: <p><button type=button onclick="openViewer()">Open a new
626: viewer</button></p>
627: <p>Each viewer opens in a new window. You can have as many viewers
628: as you like, they all view the same data.</p>
629: </body>
1.155 ihickson 630: </html></pre><p>The viewer is more involved:<pre><!DOCTYPE HTML>
1.81 ihickson 631: <html>
632: <head>
633: <title>Workers example: Multiviewer viewer</title>
634: <script>
1.50 ihickson 635: var worker = new SharedWorker('worker.js', 'core');
1.36 ihickson 636:
637: // CONFIGURATION
638: function configure(event) {
1.54 ihickson 639: if (event.data.substr(0, 4) != 'cfg ') return;
640: var name = event.data.substr(4).split(' ', 1);
1.36 ihickson 641: // update display to mention our name is name
642: document.getElementsByTagName('h1')[0].textContent += ' ' + name;
643: // no longer need this listener
1.43 ihickson 644: worker.port.removeEventListener('message', configure, false);
1.36 ihickson 645: }
1.53 ihickson 646: worker.port.addEventListener('message', configure, false);
1.36 ihickson 647:
648: // MAP
649: function paintMap(event) {
1.54 ihickson 650: if (event.data.substr(0, 4) != 'map ') return;
651: var data = event.data.substr(4).split(',');
1.36 ihickson 652: // display tiles data[0] .. data[8]
653: var canvas = document.getElementById('map');
654: var context = canvas.getContext('2d');
655: for (var y = 0; y < 3; y += 1) {
656: for (var x = 0; x < 3; x += 1) {
657: var tile = data[y * 3 + x];
658: if (tile == '0')
659: context.fillStyle = 'green';
660: else
661: context.fillStyle = 'maroon';
662: fillRect(x * 50, y * 50, 50, 50);
663: }
664: }
665: }
1.53 ihickson 666: worker.port.addEventListener('message', paintMap, false);
1.36 ihickson 667:
668: // PUBLIC CHAT
669: function updatePublicChat(event) {
1.54 ihickson 670: if (event.data.substr(0, 4) != 'txt ') return;
671: var name = event.data.substr(4).split(' ', 1);
672: var message = event.data.substr(4 + length(name) + 1);
1.81 ihickson 673: // display "<name> message" in public chat
1.36 ihickson 674: var dialog = document.getElementById('public');
675: var dt = document.createElement('dt');
676: dt.textContent = name;
677: dialog.appendChild(dt);
678: var dd = document.createElement('dd');
679: dd.textContent = message;
680: dialog.appendChild(dd);
681: }
1.53 ihickson 682: worker.port.addEventListener('message', updatePublicChat, false);
1.36 ihickson 683:
684: // PRIVATE CHAT
685: function startPrivateChat(event) {
1.54 ihickson 686: if (event.data.substr(0, 4) != 'msg ') return;
687: var name = event.data.substr(4).split(' ', 1);
1.84 ihickson 688: var port = event.ports[0];
1.36 ihickson 689: // display a private chat UI
690: var ul = document.getElementById('private');
691: var li = document.createElement('li');
692: var h3 = document.createElement('h3');
693: h3.textContent = 'Private chat with ' + name;
694: li.appendChild(h3);
695: var dialog = document.createElement('dialog');
696: var addMessage = function(name, message) {
697: var dt = document.createElement('dt');
698: dt.textContent = name;
699: dialog.appendChild(dt);
700: var dd = document.createElement('dd');
701: dd.textContent = message;
702: dialog.appendChild(dd);
703: };
704: port.onmessage = function (event) {
1.54 ihickson 705: addMessage(name, event.data);
1.36 ihickson 706: };
707: li.appendChild(dialog);
708: var form = document.createElement('form');
709: var p = document.createElement('p');
710: var input = document.createElement('input');
711: input.size = 50;
712: p.appendChild(input);
713: p.appendChild(document.createTextNode(' '));
714: var button = document.createElement('button');
715: button.textContent = 'Post';
716: p.appendChild(button);
717: form.onsubmit = function () {
718: port.postMessage(input.value);
719: addMessage('me', input.value);
720: input.value = '';
721: return false;
722: };
723: form.appendChild(p);
724: li.appendChild(form);
725: }
1.53 ihickson 726: worker.port.addEventListener('message', startPrivateChat, false);
1.188 ihickson 727:
728: worker.port.start();
1.81 ihickson 729: </script>
730: </head>
731: <body>
732: <h1>Viewer</h1>
733: <h2>Map</h2>
734: <p><canvas id="map" height=150 width=150></canvas></p>
735: <p>
736: <button type=button onclick="worker.port.postMessage('mov left')">Left</button>
737: <button type=button onclick="worker.port.postMessage('mov up')">Up</button>
738: <button type=button onclick="worker.port.postMessage('mov down')">Down</button>
739: <button type=button onclick="worker.port.postMessage('mov right')">Right</button>
740: <button type=button onclick="worker.port.postMessage('set 0')">Set 0</button>
741: <button type=button onclick="worker.port.postMessage('set 1')">Set 1</button>
742: </p>
743: <h2>Public Chat</h2>
744: <dialog id="public"></dialog>
745: <form onsubmit="worker.port.postMessage('txt ' + message.value); message.value = ''; return false;">
746: <p>
747: <input type="text" name="message" size="50">
748: <button>Post</button>
749: </p>
750: </form>
751: <h2>Private Chat</h2>
752: <ul id="private"></ul>
753: </body>
754: </html>
1.155 ihickson 755: </pre><p>There are several key things worth noting about the way the
756: viewer is written.<p><strong>Multiple listeners</strong>. Instead of a single message
1.81 ihickson 757: processing function, the code here attaches multiple event
758: listeners, each one performing a quick check to see if it is
759: relevant for the message. In this example it doesn't make much
760: difference, but if multiple authors wanted to collaborate using a
761: single port to communicate with a worker, it would allow for
762: independent code instead of changes having to all be made to a
1.155 ihickson 763: single event handling function.<p>Registering event listeners in this way also allows you to
1.81 ihickson 764: unregister specific listeners when you are done with them, as is
765: done with the <code title="">configure()</code> method in this
1.155 ihickson 766: example.<p>Finally, the worker:<pre>
767: var nextName = 0;
1.36 ihickson 768: function getNextName() {
769: // this could use more friendly names
770: // but for now just return a number
771: return nextName++;
772: }
773:
774: var map = [
775: [0, 0, 0, 0, 0, 0, 0],
776: [1, 1, 0, 1, 0, 1, 1],
777: [0, 1, 0, 1, 0, 0, 0],
778: [0, 1, 0, 1, 0, 1, 1],
779: [0, 0, 0, 1, 0, 0, 0],
780: [1, 0, 0, 1, 1, 1, 1],
781: [1, 1, 0, 1, 1, 0, 1],
782: ];
783:
784: function wrapX(x) {
785: if (x < 0) return wrapX(x + map[0].length);
1.81 ihickson 786: if (x >= map[0].length) return wrapX(x - map[0].length);
1.36 ihickson 787: return x;
788: }
789:
790: function wrapY(y) {
791: if (y < 0) return wrapY(y + map.length);
1.81 ihickson 792: if (y >= map[0].length) return wrapY(y - map.length);
1.36 ihickson 793: return y;
794: }
795:
1.50 ihickson 796: function sendMapData(callback) {
1.36 ihickson 797: var data = '';
798: for (var y = viewer.y-1; y <= viewer.y+1; y += 1) {
799: for (var x = viewer.x-1; x <= viewer.x+1; x += 1) {
800: if (data != '')
801: data += ',';
802: data += map[y][x];
803: }
804: }
1.50 ihickson 805: callback('map ' + data);
1.36 ihickson 806: }
807:
808: var viewers = {};
809: onconnect = function (event) {
1.84 ihickson 810: event.ports[0]._name = getNextName();
811: event.ports[0]._data = { port: event.port, x: 0, y: 0, };
812: viewers[event.ports[0]._name] = event.port._data;
813: event.ports[0].postMessage('cfg ' + name);
814: event.ports[0].onmessage = getMessage;
815: sendMapData(event.ports[0].postMessage);
1.36 ihickson 816: };
817:
818: function getMessage(event) {
1.54 ihickson 819: switch (event.data.substr(0, 4)) {
1.36 ihickson 820: case 'mov ':
1.54 ihickson 821: var direction = event.data.substr(4);
1.36 ihickson 822: var dx = 0;
823: var dy = 0;
824: switch (direction) {
825: case 'up': dy = -1; break;
826: case 'down': dy = 1; break;
827: case 'left': dx = -1; break;
828: case 'right': dx = 1; break;
829: }
830: event.target._data.x = wrapX(event.target._data.x + dx);
831: event.target._data.y = wrapY(event.target._data.y + dy);
1.50 ihickson 832: sendMapData(event.target.postMessage);
1.36 ihickson 833: break;
834: case 'set ':
1.54 ihickson 835: var value = event.data.substr(4);
1.36 ihickson 836: map[event.target._data.y][event.target._data.x] = value;
837: for (var viewer in viewers)
1.50 ihickson 838: sendMapData(viewers[viewer].port.postMessage);
1.36 ihickson 839: break;
840: case 'txt ':
841: var name = event.target._name;
1.54 ihickson 842: var message = event.data.substr(4);
1.36 ihickson 843: for (var viewer in viewers)
844: viewers[viewer].port.postMessage('txt ' + name + ' ' + message);
845: break;
846: case 'msg ':
847: var party1 = event._data;
1.54 ihickson 848: var party2 = viewers[event.data.substr(4).split(' ', 1)];
1.36 ihickson 849: if (party2) {
850: var channel = new MessageChannel();
1.84 ihickson 851: party1.port.postMessage('msg ' + party2.name, [channel.port1]);
852: party2.port.postMessage('msg ' + party1.name, [channel.port2]);
1.36 ihickson 853: }
854: break;
855: }
1.155 ihickson 856: }</pre><p><strong>Connecting to multiple pages</strong>. The script uses
1.115 ihickson 857: the <code title="handler-SharedWorkerGlobalScope-onconnect"><a href="#handler-sharedworkerglobalscope-onconnect">onconnect</a></code>
1.155 ihickson 858: event listener to listen for multiple connections.<p><strong>Direct channels</strong>. When the worker receives a
1.81 ihickson 859: "msg" message from one viewer naming another viewer, it sets up a
860: direct connection between the two, so that the two viewers can
861: communicate directly without the worker having to proxy all the
1.238 ihickson 862: messages.<p><a href="http://www.whatwg.org/demos/workers/multiviewer/page.html">View this example online</a>.<h4 id="delegation"><span class="secno">1.2.6 </span>Delegation</h4><p><i>This section is non-normative.</i><p>With multicore CPUs becoming prevalent, one way to obtain better
1.81 ihickson 863: performance is to split computationally expensive tasks amongst
864: multiple workers. In this example, a computationally expensive task
865: that is to be performed for every number from 1 to 10,000,000 is
1.155 ihickson 866: farmed out to ten subworkers.<p>The main page is as follows, it just reports the result:<pre><!DOCTYPE HTML>
1.81 ihickson 867: <html>
868: <head>
1.203 ihickson 869: <title>Worker example: Multicore computation</title>
1.81 ihickson 870: </head>
871: <body>
1.203 ihickson 872: <p>Result: <output id="result"></output></p>
1.81 ihickson 873: <script>
1.50 ihickson 874: var worker = new Worker('worker.js');
875: worker.onmessage = function (event) {
1.54 ihickson 876: document.getElementById('result').textContent = event.data;
1.40 ihickson 877: };
1.81 ihickson 878: </script>
879: </body>
1.155 ihickson 880: </html></pre><p>The worker itself is as follows:<pre>// settings
1.40 ihickson 881: var num_workers = 10;
882: var items_per_worker = 1000000;
883:
884: // start the workers
885: var result = 0;
886: var pending_workers = num_workers;
887: for (var i = 0; i < num_workers; i += 1) {
1.50 ihickson 888: var worker = new Worker('core.js');
889: worker.postMessage(i * items_per_worker);
890: worker.postMessage((i+1) * items_per_worker);
891: worker.onmessage = storeResult;
1.40 ihickson 892: }
893:
894: // handle the results
895: function storeResult(event) {
1.54 ihickson 896: result += 1*event.data;
1.40 ihickson 897: pending_workers -= 1;
898: if (pending_workers <= 0)
1.50 ihickson 899: postMessage(result); // finished!
1.155 ihickson 900: }</pre><p>It consists of a loop to start the subworkers, and then a handler
901: that waits for all the subworkers to respond.<p>The subworkers are implemented as follows:<pre>var start;
1.41 ihickson 902: onmessage = getStart;
1.40 ihickson 903: function getStart(event) {
1.54 ihickson 904: start = 1*event.data;
1.40 ihickson 905: onmessage = getEnd;
906: }
907:
908: var end;
909: function getEnd(event) {
1.54 ihickson 910: end = 1*event.data;
1.40 ihickson 911: onmessage = null;
1.66 ihickson 912: work();
1.40 ihickson 913: }
914:
1.66 ihickson 915: function work() {
1.40 ihickson 916: var result = 0;
917: for (var i = start; i < end; i += 1) {
918: // perform some complex calculation here
919: result += 1;
920: }
1.50 ihickson 921: postMessage(result);
922: close();
1.155 ihickson 923: }</pre><p>They receive two numbers in two events, perform the computation
1.81 ihickson 924: for the range of numbers thus specified, and then report the result
1.238 ihickson 925: back to the parent.<p><a href="http://www.whatwg.org/demos/workers/multicore/page.html">View this example online</a>.<h4 id="providing-libraries"><span class="secno">1.2.7 </span>Providing libraries</h4><p><i>This section is non-normative.</i><p>Suppose that a cryptography library is made available that
1.155 ihickson 926: provides three tasks:<dl><dt>Generate a public/private key pair</dt>
1.81 ihickson 927:
928: <dd>Takes a port, on which it will send two messages, first the
929: public key and then the private key.</dd>
930:
931: <dt>Given a plaintext and a public key, return the corresponding cyphertext</dt>
932:
933: <dd>Takes a port, to which any number of messages can be sent, the
934: first giving the public key, and the remainder giving the
935: plaintext, each of which is encrypted and then sent on that same
936: channel as the cyphertext. The user can close the port when it is
937: done encrypting content.</dd>
938:
939: <dt>Given a cyphertext and a private key, return the corresponding plaintext</dt>
940:
941: <dd>Takes a port, to which any number of messages can be sent, the
942: first giving the private key, and the remainder giving the
943: cyphertext, each of which is decrypted and then sent on that same
944: channel as the plaintext. The user can close the port when it is
945: done decrypting content.</dd>
1.49 ihickson 946:
1.155 ihickson 947: </dl><p>The library itself is as follows:<pre>function handleMessage(e) {
1.54 ihickson 948: if (e.data == "genkeys")
1.84 ihickson 949: genkeys(e.ports[0]);
1.54 ihickson 950: else if (e.data == "encrypt")
1.84 ihickson 951: encrypt(e.ports[0]);
1.54 ihickson 952: else if (e.data == "decrypt")
1.84 ihickson 953: decrypt(e.ports[0]);
1.49 ihickson 954: }
955:
956: function genkeys(p) {
957: var keys = _generateKeyPair();
958: p.postMessage(keys[0]);
959: p.postMessage(keys[1]);
960: }
961:
962: function encrypt(p) {
963: var key, state = 0;
964: p.onmessage = function (e) {
965: if (state == 0) {
1.54 ihickson 966: key = e.data;
1.49 ihickson 967: state = 1;
968: } else {
1.54 ihickson 969: p.postMessage(_encrypt(key, e.data));
1.49 ihickson 970: }
971: };
972: }
973:
974: function decrypt(p) {
975: var key, state = 0;
976: p.onmessage = function (e) {
977: if (state == 0) {
1.54 ihickson 978: key = e.data;
1.49 ihickson 979: state = 1;
980: } else {
1.54 ihickson 981: p.postMessage(_decrypt(key, e.data));
1.49 ihickson 982: }
983: };
984: }
985:
1.50 ihickson 986: // support being used as a shared worker as well as a dedicated worker
1.195 ihickson 987: if ('onmessage' in this) // dedicated worker
1.50 ihickson 988: onmessage = handleMessage;
989: else // shared worker
990: onconnect = function (e) { e.port.onmessage = handleMessage; }
1.49 ihickson 991:
992:
993: // the "crypto" functions:
994:
995: function _generateKeyPair() {
996: return [Math.random(), Math.random()];
997: }
998:
999: function _encrypt(k, s) {
1000: return 'encrypted-' + k + ' ' + s;
1001: }
1002:
1003: function _decrypt(k, s) {
1004: return s.substr(s.indexOf(' ')+1);
1.155 ihickson 1005: }</pre><p>Note that the crypto functions here are just stubs and don't do
1006: real cryptography.<p>This library could be used as follows:<pre><!DOCTYPE HTML>
1.81 ihickson 1007: <html>
1008: <head>
1009: <title>Worker example: Crypto library</title>
1010: <script>
1.50 ihickson 1011: var crytoLib = new Worker('libcrypto-v1.js'); // or could use 'libcrypto-v2.js'
1.49 ihickson 1012: function getKeys() {
1013: var state = 0;
1.50 ihickson 1014: cryptoLib.startConversation("genkeys").onmessage = function (e) {
1.49 ihickson 1015: if (state == 0)
1.54 ihickson 1016: document.getElementById('public').value = e.data;
1.49 ihickson 1017: else if (state == 1)
1.54 ihickson 1018: document.getElementById('private').value = e.data;
1.49 ihickson 1019: state += 1;
1020: };
1021: }
1022: function enc() {
1.50 ihickson 1023: var port = cryptoLib.startConversation("encrypt");
1024: port.postMessage(document.getElementById('public').value);
1025: port.postMessage(document.getElementById('input').value);
1026: port.onmessage = function (e) {
1.54 ihickson 1027: document.getElementById('input').value = e.data;
1.50 ihickson 1028: port.close();
1.49 ihickson 1029: };
1030: }
1031: function dec() {
1.50 ihickson 1032: var port = cryptoLib.startConversation("decrypt");
1033: port.postMessage(document.getElementById('private').value);
1034: port.postMessage(document.getElementById('input').value);
1035: port.onmessage = function (e) {
1.54 ihickson 1036: document.getElementById('input').value = e.data;
1.50 ihickson 1037: port.close();
1.49 ihickson 1038: };
1039: }
1.81 ihickson 1040: </script>
1041: <style>
1.49 ihickson 1042: textarea { display: block; }
1.81 ihickson 1043: </style>
1044: </head>
1045: <body onload="getKeys()">
1046: <fieldset>
1047: <legend>Keys</legend>
1048: <p><label>Public Key: <textarea id="public"></textarea></label></p>
1049: <p><label>Private Key: <textarea id="private"></textarea></label></p>
1050: </fieldset>
1051: <p><label>Input: <textarea id="input"></textarea></label></p>
1052: <p><button onclick="enc()">Encrypt</button> <button onclick="dec()">Decrypt</button></p>
1053: </body>
1.155 ihickson 1054: </html></pre><p>A later version of the API, though, might want to offload all the
1055: crypto work onto subworkers. This could be done as follows:<pre>function handleMessage(e) {
1.54 ihickson 1056: if (e.data == "genkeys")
1.84 ihickson 1057: genkeys(e.ports[0]);
1.54 ihickson 1058: else if (e.data == "encrypt")
1.84 ihickson 1059: encrypt(e.ports[0]);
1.54 ihickson 1060: else if (e.data == "decrypt")
1.84 ihickson 1061: decrypt(e.ports[0]);
1.49 ihickson 1062: }
1063:
1064: function genkeys(p) {
1.50 ihickson 1065: var generator = new Worker('libcrypto-v2-generator.js');
1.84 ihickson 1066: generator.postMessage('', [p]);
1.49 ihickson 1067: }
1068:
1069: function encrypt(p) {
1070: p.onmessage = function (e) {
1.54 ihickson 1071: var key = e.data;
1.50 ihickson 1072: var encryptor = new Worker('libcrypto-v2-encryptor.js');
1.84 ihickson 1073: encryptor.postMessage(key, [p]);
1.49 ihickson 1074: };
1075: }
1076:
1077: function encrypt(p) {
1078: p.onmessage = function (e) {
1.54 ihickson 1079: var key = e.data;
1.50 ihickson 1080: var decryptor = new Worker('libcrypto-v2-decryptor.js');
1.84 ihickson 1081: decryptor.postMessage(key, [p]);
1.49 ihickson 1082: };
1083: }
1084:
1.50 ihickson 1085: // support being used as a shared worker as well as a dedicated worker
1.195 ihickson 1086: if ('onmessage' in this) // dedicated worker
1.50 ihickson 1087: onmessage = handleMessage;
1088: else // shared worker
1.84 ihickson 1089: onconnect = function (e) { e.ports[0].onmessage = handleMessage };
1.155 ihickson 1090: </pre><p>The little subworkers would then be as follows.<p>For generating key pairs:<pre>onmessage = function (e) {
1.50 ihickson 1091: var k = _generateKeyPair();
1.84 ihickson 1092: e.ports[0].postMessage(k[0]);
1093: e.ports[0].postMessage(k[1]);
1.49 ihickson 1094: close();
1095: }
1.50 ihickson 1096:
1097: function _generateKeyPair() {
1098: return [Math.random(), Math.random()];
1.155 ihickson 1099: }</pre><p>For encrypting:<pre>onmessage = function (e) {
1.54 ihickson 1100: var key = e.data;
1.84 ihickson 1101: e.ports[0].onmessage = function (e) {
1.54 ihickson 1102: var s = e.data;
1.50 ihickson 1103: postMessage(_encrypt(key, s));
1.49 ihickson 1104: }
1.50 ihickson 1105: }
1106:
1107: function _encrypt(k, s) {
1108: return 'encrypted-' + k + ' ' + s;
1.155 ihickson 1109: }</pre><p>For decrypting:<pre>onmessage = function (e) {
1.54 ihickson 1110: var key = e.data;
1.84 ihickson 1111: e.ports[0].onmessage = function (e) {
1.54 ihickson 1112: var s = e.data;
1.50 ihickson 1113: postMessage(_decrypt(key, s));
1.49 ihickson 1114: }
1.50 ihickson 1115: }
1116:
1117: function _decrypt(k, s) {
1118: return s.substr(s.indexOf(' ')+1);
1.155 ihickson 1119: }</pre><p>Notice how the users of the API don't have to even know that this
1120: is happening — the API hasn't changed; the library can
1.81 ihickson 1121: delegate to subworkers without changing its API, even though it is
1.155 ihickson 1122: accepting data using message channels.<p><a href="http://www.whatwg.org/demos/workers/crypto/page.html">View this example online</a>.<h2 id="conformance-requirements"><span class="secno">2 </span>Conformance requirements</h2><p>All diagrams, examples, and notes in this specification are
1.81 ihickson 1123: non-normative, as are all sections explicitly marked non-normative.
1.155 ihickson 1124: Everything else in this specification is normative.<p>The key words "MUST", "MUST NOT", "REQUIRED", <!--"SHALL", "SHALL
1.81 ihickson 1125: NOT",--> "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and
1126: "OPTIONAL" in the normative parts of this document are to be
1127: interpreted as described in RFC2119. For readability, these words do
1.155 ihickson 1128: not appear in all uppercase letters in this specification. <a href="#refsRFC2119">[RFC2119]</a><p>Requirements phrased in the imperative as part of algorithms
1.81 ihickson 1129: (such as "strip any leading space characters" or "return false and
1130: abort these steps") are to be interpreted with the meaning of the
1131: key word ("must", "should", "may", etc) used in introducing the
1.155 ihickson 1132: algorithm.<p>Some conformance requirements are phrased as requirements on
1.81 ihickson 1133: attributes, methods or objects. Such requirements are to be
1.155 ihickson 1134: interpreted as requirements on user agents.<p>Conformance requirements phrased as algorithms or specific steps
1.81 ihickson 1135: may be implemented in any manner, so long as the end result is
1136: equivalent. (In particular, the algorithms defined in this
1137: specification are intended to be easy to follow, and not intended to
1.155 ihickson 1138: be performant.)<p>The only conformance class defined by this specification is user
1139: agents.<p>User agents may impose implementation-specific limits on
1.81 ihickson 1140: otherwise unconstrained inputs, e.g. to prevent denial of service
1141: attacks, to guard against running out of memory, or to work around
1.229 ihickson 1142: platform-specific limitations.<p>When support for a feature is disabled (e.g. as an emergency
1143: measure to mitigate a security problem, or to aid in development, or
1144: for performance reasons), user agents must act as if they had no
1145: support for the feature whatsoever, and as if the feature was not
1146: mentioned in this specification. For example, if a particular
1147: feature is accessed via an attribute in a Web IDL interface, the
1148: attribute itself would be omitted from the objects that implement
1149: that interface — leaving the attribute on the object but
1150: making it return null or throw an exception is insufficient.<h3 id="dependencies"><span class="secno">2.1 </span>Dependencies</h3><p>This specification relies on several other underlying
1.226 ihickson 1151: specifications.<dl><dt>HTML</dt>
1.49 ihickson 1152:
1.81 ihickson 1153: <dd>
1.49 ihickson 1154:
1.226 ihickson 1155: <p>Many fundamental concepts from HTML are used by this
1156: specification. <a href="#refsHTML">[HTML]</a></p>
1.49 ihickson 1157:
1.81 ihickson 1158: </dd>
1.1 ihickson 1159:
1.81 ihickson 1160: <dt>WebIDL</dt>
1.1 ihickson 1161:
1162: <dd>
1163:
1.81 ihickson 1164: <p>The IDL blocks in this specification use the semantics of the
1.153 ihickson 1165: WebIDL specification. <a href="#refsWEBIDL">[WEBIDL]</a></p>
1.1 ihickson 1166:
1.81 ihickson 1167: </dd>
1.1 ihickson 1168:
1.155 ihickson 1169: </dl><h2 id="terminology"><span class="secno">3 </span>Terminology</h2><p>The construction "a <code title="">Foo</code> object", where
1.81 ihickson 1170: <code title="">Foo</code> is actually an interface, is sometimes
1171: used instead of the more accurate "an object implementing the
1.155 ihickson 1172: interface <code title="">Foo</code>".<p>The term DOM is used to refer to the API set made available to
1.81 ihickson 1173: scripts in Web applications, and does not necessarily imply the
1174: existence of an actual <code>Document</code> object or of any other
1175: <code>Node</code> objects as defined in the DOM Core
1.171 ihickson 1176: specifications. <a href="#refsDOMCORE">[DOMCORE]</a><p>An IDL attribute is said to be <em>getting</em> when its value is
1.81 ihickson 1177: being retrieved (e.g. by author script), and is said to be
1.155 ihickson 1178: <em>setting</em> when a new value is assigned to it.<p>The term "JavaScript" is used to refer to ECMA262, rather than
1.103 ihickson 1179: the official term ECMAScript, since the term JavaScript is more
1.155 ihickson 1180: widely known. <a href="#refsECMA262">[ECMA262]</a><h2 id="infrastructure"><span class="secno">4 </span>Infrastructure</h2><p>There are two kinds of workers; dedicated workers, and shared
1.81 ihickson 1181: workers. Dedicated workers, once created, and are linked to their
1182: creator; but message ports can be used to communicate from a
1183: dedicated worker to multiple other browsing contexts or
1184: workers. Shared workers, on the other hand, are named, and once
1185: created any script running in the same <span>origin</span> can
1.155 ihickson 1186: obtain a reference to that worker and communicate with it.<h3 id="the-global-scope"><span class="secno">4.1 </span>The global scope</h3><p>The global scope is the "inside" of a worker.<h4 id="the-workerglobalscope-abstract-interface"><span class="secno">4.1.1 </span>The <code><a href="#workerglobalscope">WorkerGlobalScope</a></code> abstract interface</h4><pre class="idl">interface <dfn id="workerglobalscope">WorkerGlobalScope</dfn> {
1.115 ihickson 1187: readonly attribute <a href="#workerglobalscope">WorkerGlobalScope</a> <a href="#dom-workerglobalscope-self" title="dom-WorkerGlobalScope-self">self</a>;
1188: readonly attribute <a href="#workerlocation">WorkerLocation</a> <a href="#dom-workerglobalscope-location" title="dom-WorkerGlobalScope-location">location</a>;
1189:
1190: void <a href="#dom-workerglobalscope-close" title="dom-WorkerGlobalScope-close">close</a>();
1.144 ihickson 1191: <!-- v2-onclose attribute <span>Function</span> <span title="handler-WorkerGlobalScope-onclose">onclose</span>;
1192: --> attribute <span>Function</span> <a href="#handler-workerglobalscope-onerror" title="handler-WorkerGlobalScope-onerror">onerror</a>;
1.150 ihickson 1193: };
1.172 ihickson 1194: <a href="#workerglobalscope">WorkerGlobalScope</a> implements <a href="#workerutils">WorkerUtils</a>;
1195: <a href="#workerglobalscope">WorkerGlobalScope</a> implements <span>EventTarget</span>;</pre><p>The <dfn id="dom-workerglobalscope-self" title="dom-WorkerGlobalScope-self"><code>self</code></dfn> attribute
1.155 ihickson 1196: must return the <code><a href="#workerglobalscope">WorkerGlobalScope</a></code> object itself.<p>The <dfn id="dom-workerglobalscope-location" title="dom-WorkerGlobalScope-location"><code>location</code></dfn>
1.115 ihickson 1197: attribute must return the <code><a href="#workerlocation">WorkerLocation</a></code> object created
1198: for the <code><a href="#workerglobalscope">WorkerGlobalScope</a></code> object when the worker was
1.81 ihickson 1199: created. It represents the <span>absolute URL</span> of the script
1.155 ihickson 1200: that was used to initialize the worker, after any redirects.<hr><p>When a script invokes the <dfn id="dom-workerglobalscope-close" title="dom-WorkerGlobalScope-close"><code>close()</code></dfn>
1.123 ihickson 1201: method on a <code><a href="#workerglobalscope">WorkerGlobalScope</a></code> object, the user agent
1.155 ihickson 1202: must run the following steps (atomically):<ol><li><p>Discard any <span title="concept-task">tasks</span> that
1.123 ihickson 1203: have been added to the <span>event loop</span>'s <span title="task
1204: queue">task queues</span>.</p>
1205:
1206: <!-- v2-onclose
1207: <li><p><span>Queue a task</span> to <span>fire a simple
1.179 ihickson 1208: event</span> named <code title="event-close">close</code> at the
1.123 ihickson 1209: <code>WorkerGlobalScope</code> object.</p></li>
1210: -->
1.81 ihickson 1211:
1.115 ihickson 1212: <li><p>Set the worker's <code><a href="#workerglobalscope">WorkerGlobalScope</a></code> object's
1213: <a href="#dom-workerglobalscope-closing" title="dom-WorkerGlobalScope-closing">closing</a> flag to
1.123 ihickson 1214: true. (This prevents any further tasks from being queued.)</li>
1.81 ihickson 1215:
1.177 ihickson 1216: </ol><p>The following are the <span>event handlers</span> (and their
1217: corresponding <span title="event handler event type">event handler
1218: event types</span>) that must be supported, as IDL attributes, by
1219: objects implementing the <code><a href="#workerglobalscope">WorkerGlobalScope</a></code>
1220: interface:<table><thead><tr><th><span title="event handlers">Event handler</span> <th><span>Event handler event type</span>
1.155 ihickson 1221: <tbody><!-- v2-onclose <tr><td><dfn title="handler-WorkerGlobalScope-onclose"><code>onclose</code></dfn> <td> <code title="event-close">close</code> --><tr><td><dfn id="handler-workerglobalscope-onerror" title="handler-WorkerGlobalScope-onerror"><code>onerror</code></dfn> <td> <code title="event-error">error</code>
1.209 ihickson 1222: </table><hr><p>The <code><a href="#workerglobalscope">WorkerGlobalScope</a></code> interface must not exist if
1223: the interface's <span>relevant namespace object</span> is a
1224: <code>Window</code> object. <a href="#refsWEBIDL">[WEBIDL]</a><h4 id="dedicated-workers-and-the-dedicatedworkerglobalscope-interface"><span class="secno">4.1.2 </span>Dedicated workers and the <code><a href="#dedicatedworkerglobalscope">DedicatedWorkerGlobalScope</a></code> interface</h4><pre class="idl">[Supplemental, NoInterfaceObject]
1.150 ihickson 1225: interface <dfn id="dedicatedworkerglobalscope">DedicatedWorkerGlobalScope</dfn> : <a href="#workerglobalscope">WorkerGlobalScope</a> {
1.174 ihickson 1226: void <a href="#dom-dedicatedworkerglobalscope-postmessage" title="dom-DedicatedWorkerGlobalScope-postMessage">postMessage</a>(in any message, in optional <span>MessagePortArray</span> ports);<!--
1.77 ihickson 1227: <span>MessagePort</span> <span title="dom-DedicatedWorkerGlobalScope-startConversation">startConversation</span>(in any message);-->
1.144 ihickson 1228: attribute <span>Function</span> <a href="#handler-dedicatedworkerglobalscope-onmessage" title="handler-DedicatedWorkerGlobalScope-onmessage">onmessage</a>;
1.155 ihickson 1229: };</pre><p><code><a href="#dedicatedworkerglobalscope">DedicatedWorkerGlobalScope</a></code> objects act as if they
1.81 ihickson 1230: had an implicit <code>MessagePort</code> associated with them. This
1231: port is part of a channel that is set up when the worker is created,
1232: but it is not exposed. This object must never be garbage collected
1.155 ihickson 1233: before the <code><a href="#dedicatedworkerglobalscope">DedicatedWorkerGlobalScope</a></code> object.<p>All messages received by that port must immediately be retargeted
1234: at the <code><a href="#dedicatedworkerglobalscope">DedicatedWorkerGlobalScope</a></code> object.<p>The <dfn id="dom-dedicatedworkerglobalscope-postmessage" title="dom-DedicatedWorkerGlobalScope-postMessage"><code>postMessage()</code></dfn><!--
1.64 ihickson 1235: and <dfn
1236: title="dom-DedicatedWorkerGlobalScope-startConversation"><code>startConversation()</code></dfn>-->
1.81 ihickson 1237: method<!--s (startConversation)--> on
1.115 ihickson 1238: <code><a href="#dedicatedworkerglobalscope">DedicatedWorkerGlobalScope</a></code> objects must act as if, when
1.81 ihickson 1239: invoked, it<!--/they (startConversation)--> immediately invoked the
1240: method of the same name on the port, with the same arguments, and
1.177 ihickson 1241: returned the same return value.<p>The following are the <span>event handlers</span> (and their
1242: corresponding <span title="event handler event type">event handler
1243: event types</span>) that must be supported, as IDL attributes, by
1244: objects implementing the <code><a href="#dedicatedworkerglobalscope">DedicatedWorkerGlobalScope</a></code>
1245: interface:<table><thead><tr><th><span title="event handlers">Event handler</span> <th><span>Event handler event type</span>
1.155 ihickson 1246: <tbody><tr><td><dfn id="handler-dedicatedworkerglobalscope-onmessage" title="handler-DedicatedWorkerGlobalScope-onmessage"><code>onmessage</code></dfn> <td> <code title="event-message">message</code>
1.191 ihickson 1247: </table><p>For the purposes of the <span>application cache</span> networking
1248: model, a dedicated worker is an extension of the <span>cache
1.270 ihickson 1249: host</span> from which it was created.<h4 id="shared-workers-and-the-sharedworkerglobalscope-interface"><span class="secno">4.1.3 </span>Shared workers and the <code><a href="#sharedworkerglobalscope">SharedWorkerGlobalScope</a></code> interface</h4><pre class="idl">[Supplemental, NoInterfaceObject]
1.150 ihickson 1250: interface <dfn id="sharedworkerglobalscope">SharedWorkerGlobalScope</dfn> : <a href="#workerglobalscope">WorkerGlobalScope</a> {
1.115 ihickson 1251: readonly attribute DOMString <a href="#dom-sharedworkerglobalscope-name" title="dom-SharedWorkerGlobalScope-name">name</a>;
1.181 ihickson 1252: readonly attribute <span>ApplicationCache</span> <span title="dom-SharedWorkerGlobalScope-applicationCache">applicationCache</span>;
1.144 ihickson 1253: attribute <span>Function</span> <a href="#handler-sharedworkerglobalscope-onconnect" title="handler-SharedWorkerGlobalScope-onconnect">onconnect</a>;
1.155 ihickson 1254: };</pre><p>Shared workers receive message ports through <code title="event-WorkerGlobalScope-connect">connect</code> events on
1255: their global object for each connection.<p>The <dfn id="dom-sharedworkerglobalscope-name" title="dom-SharedWorkerGlobalScope-name"><code>name</code></dfn>
1.81 ihickson 1256: attribute must return the value it was assigned when the
1.115 ihickson 1257: <code><a href="#sharedworkerglobalscope">SharedWorkerGlobalScope</a></code> object was created by the
1258: "<a href="#run-a-worker">run a worker</a>" algorithm. Its value represents the name
1.81 ihickson 1259: that can be used to obtain a reference to the worker using the
1.177 ihickson 1260: <code><a href="#sharedworker">SharedWorker</a></code> constructor.<p>The following are the <span>event handlers</span> (and their
1261: corresponding <span title="event handler event type">event handler
1262: event types</span>) that must be supported, as IDL attributes, by
1263: objects implementing the <code><a href="#sharedworkerglobalscope">SharedWorkerGlobalScope</a></code>
1264: interface:<table><thead><tr><th><span title="event handlers">Event handler</span> <th><span>Event handler event type</span>
1.155 ihickson 1265: <tbody><tr><td><dfn id="handler-sharedworkerglobalscope-onconnect" title="handler-SharedWorkerGlobalScope-onconnect"><code>onconnect</code></dfn> <td> <code title="event-connect">connect</code>
1.191 ihickson 1266: </table><p>For the purposes of the <span>application cache</span> networking
1267: model, a shared worker is its own <span>cache host</span>. The
1268: <a href="#run-a-worker">run a worker</a> algorithm takes care of associating the
1269: worker with an <span>application cache</span>.<p class="note">The <code title="dom-SharedWorkerGlobalScope-applicationCache">applicationCache</code>
1.123 ihickson 1270: attribute returns the <code>ApplicationCache</code> object for the
1.101 ihickson 1271: worker.</p><!-- normative conf criteria is in the appcache section
1.160 ihickson 1272: --><h3 id="origins-of-workers"><span class="secno">4.2 </span>Origins of workers</h3><p>Both the <span>origin</span> and <span>effective script
1.81 ihickson 1273: origin</span> of scripts running in workers are the
1274: <span>origin</span> of the <span>absolute URL</span> given in that
1.115 ihickson 1275: the worker's <code title="dom-WorkerGlobalScope-location"><a href="#dom-workerglobalscope-location">location</a></code> attribute
1.186 ihickson 1276: represents.<h3 id="the-event-loop"><span class="secno">4.3 </span>The event loop</h3><p>Each <code><a href="#workerglobalscope">WorkerGlobalScope</a></code> object has an <span>event
1.128 ihickson 1277: loop</span> distinct from those defined for <span title="unit of
1278: related similar-origin browsing contexts">units of related
1279: similar-origin browsing contexts</span>. This <span>event
1280: loop</span> has no associated <span>browsing context</span>, and its
1281: <span title="task queue">task queues</span> only have events,
1282: callbacks, and networking activity as <span title="concept-task">tasks</span>. The processing model of these
1283: <span title="event loop">event loops</span> is defined below in the
1.155 ihickson 1284: <a href="#run-a-worker">run a worker</a> algorithm.<p>Each <code><a href="#workerglobalscope">WorkerGlobalScope</a></code> object also has a <dfn id="dom-workerglobalscope-closing" title="dom-WorkerGlobalScope-closing">closing</dfn> flag, which must
1.81 ihickson 1285: initially be false, but which can get set to true by the algorithms
1.155 ihickson 1286: in the processing model section below.<p>Once the <code><a href="#workerglobalscope">WorkerGlobalScope</a></code>'s <a href="#dom-workerglobalscope-closing" title="dom-WorkerGlobalScope-closing">closing</a> flag is set to
1.81 ihickson 1287: true, the <span>event loop</span>'s <span title="task queue">task
1.115 ihickson 1288: queues</span> must discard any further <span title="concept-task">tasks</span> that would be added to them (tasks
1.175 ihickson 1289: already on the queue are unaffected except where otherwise
1.115 ihickson 1290: specified). Effectively, once the <a href="#dom-workerglobalscope-closing" title="dom-WorkerGlobalScope-closing">closing</a> flag is true,
1.81 ihickson 1291: timers stop firing, notifications for all pending asynchronous
1.186 ihickson 1292: operations are dropped, etc.<h3 id="the-worker-s-lifetime"><span class="secno">4.4 </span>The worker's lifetime</h3><p>Workers communicate with other workers and with <span title="browsing context">browsing contexts</span> through <span title="channel messaging">message channels</span> and their
1.155 ihickson 1293: <code>MessagePort</code> objects.<p>Each <code><a href="#workerglobalscope">WorkerGlobalScope</a></code> <var title="">worker global
1.124 ihickson 1294: scope</var> has a list of <dfn id="the-worker-s-ports">the worker's ports</dfn>, which
1.81 ihickson 1295: consists of all the <code>MessagePort</code> objects that are
1296: entangled with another port and that have one (but only one) port
1297: owned by <var title="">worker global scope</var>. This list includes
1298: <!--all the <code>MessagePort</code> objects that are in events
1.68 ihickson 1299: pending in the <span>event loop</span>, as well as (commented out
1300: because in practice it makes no difference either way as far as I
1301: can tell, and it would be hard to strictly implement since these
1.81 ihickson 1302: ports might not yet be across the thread boundary)--> the implicit
1.155 ihickson 1303: <code>MessagePort</code> in the case of <a href="#dedicatedworkerglobalscope" title="DedicatedWorkerGlobalScope">dedicated workers</a>.<p>Each <code><a href="#workerglobalscope">WorkerGlobalScope</a></code> also has a list of <dfn id="the-worker-s-workers">the
1.124 ihickson 1304: worker's workers</dfn>. Initially this list is empty; it is
1.155 ihickson 1305: populated when the worker creates or obtains further workers.<p>Finally, each <code><a href="#workerglobalscope">WorkerGlobalScope</a></code> also has a list of
1.124 ihickson 1306: <dfn id="the-worker-s-documents">the worker's <code>Document</code>s</dfn>. Initially this list
1.155 ihickson 1307: is empty; it is populated when the worker is created.<p>Whenever a <code>Document</code> <var title="">d</var> is <dfn id="add-a-document-to-the-worker-s-documents" title="add a document to the worker's documents">added to the
1.123 ihickson 1308: worker's <code>Document</code>s</dfn>, the user agent must, for each
1.124 ihickson 1309: worker in the list of <a href="#the-worker-s-workers">the worker's workers</a> whose list
1310: of <a href="#the-worker-s-documents">the worker's <code>Document</code>s</a> does not contain
1311: <var title="">d</var>, <a href="#add-a-document-to-the-worker-s-documents" title="add a document to the worker's
1.123 ihickson 1312: documents">add <var title="">d</var> to <var title="">q</var>'s
1313: <code>WorkerGlobalScope</code> owner's list of <span>the worker's
1.155 ihickson 1314: <code>Document</code>s</span></a>.</p><!-- suggestions welcome
1315: on making this sentence into understandable English --><p>Whenever a <code>Document</code> object is <span title="discard a
1.123 ihickson 1316: Document">discarded</span>, it must be removed from the list of
1317: <a href="#the-worker-s-documents">the worker's <code>Document</code>s</a> of each worker
1.192 ihickson 1318: whose list contains that <code>Document</code>.<p>Given a <span>script's global object</span> <var title="">o</var>
1.123 ihickson 1319: when creating or obtaining a worker, the <dfn id="list-of-relevant-document-objects-to-add">list of relevant
1320: <code>Document</code> objects to add</dfn> depends on the type of
1321: <var title="">o</var>. If <var title="">o</var> is a
1322: <code><a href="#workerglobalscope">WorkerGlobalScope</a></code> object (i.e. if we are creating a
1323: nested worker), then the relevant <code>Document</code>s are the
1324: <code>Document</code>s that are in <var title="">o</var>'s own list
1325: of <a href="#the-worker-s-documents">the worker's <code>Document</code>s</a>. Otherwise, <var title="">o</var> is a <code>Window</code> object, and the relevant
1326: <code>Document</code> is just the <code>Document</code> that is the
1.155 ihickson 1327: <span>active document</span> of the <code>Window</code> object <var title="">o</var>.<hr><p>A worker is said to be a <dfn id="permissible-worker">permissible worker</dfn> if its
1.123 ihickson 1328: list of <a href="#the-worker-s-documents">the worker's <code>Document</code>s</a> is not
1.155 ihickson 1329: empty.<p>A worker is said to be a <dfn id="protected-worker">protected worker</dfn> if it is a
1.123 ihickson 1330: <a href="#permissible-worker">permissible worker</a> and either it has outstanding
1331: timers, database transactions, or network connections, or its list
1.124 ihickson 1332: of <a href="#the-worker-s-ports">the worker's ports</a> is not empty, or its
1.123 ihickson 1333: <code><a href="#workerglobalscope">WorkerGlobalScope</a></code> is actually a
1334: <code><a href="#sharedworkerglobalscope">SharedWorkerGlobalScope</a></code> object (i.e. the worker is a
1.155 ihickson 1335: shared worker).<p>A worker is said to be an <dfn id="active-needed-worker">active needed worker</dfn> if any
1.123 ihickson 1336: of the <code>Document</code> objects in <a href="#the-worker-s-documents">the worker's
1.155 ihickson 1337: <code>Document</code>s</a> are <span>fully active</span>.<p>A worker is said to be a <dfn id="suspendable-worker">suspendable worker</dfn> if it is
1.123 ihickson 1338: not an <a href="#active-needed-worker">active needed worker</a> but it is a
1.186 ihickson 1339: <a href="#permissible-worker">permissible worker</a>.<h3 id="processing-model"><span class="secno">4.5 </span>Processing model</h3><p>When a user agent is to <dfn id="run-a-worker">run a worker</dfn> for a script with
1.232 ihickson 1340: <span>URL</span> <var title="">url</var>, a <span>browsing
1341: context</span> <var title="">owner browsing context</var>, a
1342: <code>Document</code> <var title="">owner document</var>, an
1343: <span>origin</span> <var title="">owner origin</var>, and with
1344: global scope <var title="">worker global scope</var>, it must run
1345: the following steps:<ol><li>
1.81 ihickson 1346:
1347: <p>Create a completely separate and parallel execution environment
1348: (i.e. a separate thread or process or equivalent construct), and
1.106 ihickson 1349: run the rest of these steps asynchronously in that context.</p>
1.81 ihickson 1350:
1351: </li>
1.4 ihickson 1352:
1.101 ihickson 1353: <li><p>If <var title="">worker global scope</var> is actually a
1.115 ihickson 1354: <code><a href="#sharedworkerglobalscope">SharedWorkerGlobalScope</a></code> object (i.e. the worker is a
1.101 ihickson 1355: shared worker), and there are any <span title="relevant application
1356: cache">relevant application caches</span> that are identified by a
1357: manifest URL with the <span>same origin</span> as <var title="">url</var> and that have <var title="">url</var> as one of
1.115 ihickson 1358: their entries, <em>not</em> excluding entries marked as <span title="concept-appcache-foreign">foreign</span>, then associate the
1359: <var title="">worker global scope</var> with the <span title="concept-appcache-selection">most appropriate application
1.101 ihickson 1360: cache</span> of those that match.</li>
1361:
1.4 ihickson 1362: <li>
1.52 ihickson 1363:
1.256 ihickson 1364: <p>Attempt to <span>fetch</span> the resource identified by <var title="">url</var>, from the <var title="">owner origin</var>,
1365: with the <i>synchronous flag</i> set and the <i>force same-origin
1366: flag</i> set.</p> <!-- not http-origin privacy sensitive (looking
1367: forward to CORS) -->
1368:
1369: <p>If the attempt fails, then for each <code><a href="#worker">Worker</a></code> or
1370: <code><a href="#sharedworker">SharedWorker</a></code> object associated with <var title="">worker global scope</var>, <span>queue a task</span> to
1371: <span>fire a simple event</span> named <code title="event-error">error</code> at that object. Abort these
1372: steps.</p>
1.7 ihickson 1373:
1.264 ihickson 1374: <p>If the attempt succeeds, then let <var title="">source</var> be
1375: the script resource <span>decoded as UTF-8, with error
1376: handling</span>.
1377:
1378: <a href="#refsHTML">[HTML]</a>
1379:
1380: </p>
1.81 ihickson 1381:
1.68 ihickson 1382: <p>Let <var title="">language</var> be JavaScript.</p>
1.7 ihickson 1383:
1.115 ihickson 1384: <p class="note">As with <code>script</code> elements, the MIME
1.81 ihickson 1385: type of the script is ignored. Unlike with <code>script</code>
1386: elements, there is no way to override the type. It's always
1.170 ihickson 1387: assumed to be JavaScript.</p>
1.81 ihickson 1388:
1389: </li>
1.7 ihickson 1390:
1391: <li>
1.68 ihickson 1392:
1.115 ihickson 1393: <p>A new <span title="concept-script">script</span> is now
1.81 ihickson 1394: created, as follows.</p>
1395:
1396: <p>Create a new <span>script execution environment</span>
1397: set up as appropriate for the scripting language <var title="">language</var>.</p>
1.34 ihickson 1398:
1.68 ihickson 1399: <p>Parse/compile/initialize <var title="">source</var> using that
1.81 ihickson 1400: <span>script execution environment</span>, as appropriate for <var title="">language</var>, and thus obtain a <span>list of code
1401: entry-points</span>; set the <i>initial code entry-point</i> to
1402: the entry-point for any executable code to be immediately run.</p>
1403:
1404: <p>Set the <span>script's global object</span> to <var title="">worker global scope</var>.</p>
1405:
1406: <p>Set the <span>script's browsing context</span> to <var title="">owner browsing context</var>.</p>
1407:
1.232 ihickson 1408: <p>Set the <span>script's document</span> to <var title="">owner
1409: document</var>.</p>
1410:
1.83 ihickson 1411: <p>Set the <span>script's URL character encoding</span> to
1.81 ihickson 1412: UTF-8. (This is just used for encoding non-ASCII characters in the
1413: query component of URLs.)</p>
1.68 ihickson 1414:
1415: <p>Set the <span>script's base URL</span> to <var title="">url</var>.</p>
1.4 ihickson 1416:
1.81 ihickson 1417: </li>
1.4 ihickson 1418:
1419: <li>
1.81 ihickson 1420:
1421: <p><strong>Closing orphan workers</strong>: Start monitoring the
1.125 ihickson 1422: worker such that no sooner than it stops being either a
1423: <a href="#protected-worker">protected worker</a> or a <a href="#suspendable-worker">suspendable
1.123 ihickson 1424: worker</a>, and no later than it stops being a
1425: <a href="#permissible-worker">permissible worker</a>, <var title="">worker global
1426: scope</var>'s <a href="#dom-workerglobalscope-closing" title="dom-WorkerGlobalScope-closing">closing</a> flag is set
1427: to true<!-- v2-onclose and <span title="queue a task">a task is
1.179 ihickson 1428: queued</span> to <span>fire a simple event</span> named <code
1.123 ihickson 1429: title="event-close">close</code> at <var title="">worker global
1430: scope</var>-->.</p>
1.81 ihickson 1431:
1432: </li>
1.9 ihickson 1433:
1434: <li>
1.7 ihickson 1435:
1.81 ihickson 1436: <p><strong>Suspending workers</strong>: Start monitoring the
1437: worker, such that whenever <var title="">worker global
1.115 ihickson 1438: scope</var>'s <a href="#dom-workerglobalscope-closing" title="dom-WorkerGlobalScope-closing">closing</a> flag is false
1439: and the worker is a <a href="#suspendable-worker">suspendable worker</a>, the user
1.81 ihickson 1440: agent suspends execution of script in that worker until such time
1.115 ihickson 1441: as either the <a href="#dom-workerglobalscope-closing" title="dom-WorkerGlobalScope-closing">closing</a> flag switches
1442: to true or the worker stops being a <a href="#suspendable-worker">suspendable
1.81 ihickson 1443: worker</a>.</p>
1.4 ihickson 1444:
1.81 ihickson 1445: </li>
1.68 ihickson 1446:
1447: <li>
1.4 ihickson 1448:
1.81 ihickson 1449: <p><span title="jump to a code entry-point">Jump</span> to the
1.115 ihickson 1450: <span title="concept-script">script</span>'s <i>initial code
1.81 ihickson 1451: entry-point</i>, and let that run until it either returns, fails
1452: to catch an exception, or gets prematurely aborted by the
1.115 ihickson 1453: "<a href="#kill-a-worker">kill a worker</a>" or "<a href="#terminate-a-worker">terminate a worker</a>"
1.81 ihickson 1454: algorithms defined below.</p>
1455:
1.149 ihickson 1456: <!-- v2-onclose
1457: <p class="note">If the script gets aborted by the "<span>kill a
1458: worker</span>" algorithm, then that same algorithm will cause
1.115 ihickson 1459: there to only be a single <span title="concept-task">task</span>
1.81 ihickson 1460: in the <span>event loop</span> at the next step, namely the task
1.115 ihickson 1461: for the <code title="message-close">close</code> event. The
1.149 ihickson 1462: "<span>terminate a worker</span>" algorithm removes all the
1.81 ihickson 1463: events.</p>
1.149 ihickson 1464: -->
1.4 ihickson 1465:
1.81 ihickson 1466: </li>
1.4 ihickson 1467:
1.95 ihickson 1468: <li><p>If <var title="">worker global scope</var> is actually a
1.115 ihickson 1469: <code><a href="#dedicatedworkerglobalscope">DedicatedWorkerGlobalScope</a></code> object (i.e. the worker is
1.126 ihickson 1470: a dedicated worker), then enable the <span>port message
1471: queue</span> of the worker's implicit port.</li>
1.95 ihickson 1472:
1.4 ihickson 1473: <li>
1.68 ihickson 1474:
1.115 ihickson 1475: <p><i title="">Event loop</i>: Wait until either there is a <span title="concept-task">task</span> in one of the <span>event
1476: loop</span>'s <span title="task queue">task queues</span> or <var title="">worker global scope</var>'s <a href="#dom-workerglobalscope-closing" title="dom-WorkerGlobalScope-closing">closing</a> flag is set
1.81 ihickson 1477: to true.</p>
1.43 ihickson 1478:
1.81 ihickson 1479: </li>
1.4 ihickson 1480:
1481: <li>
1482:
1.81 ihickson 1483: <p>Run the oldest task on one of the <span>event loop</span>'s
1484: <span title="task queue">task queues</span>, if any. The user
1485: agent may pick any <span>task queue</span>.</p>
1486:
1.115 ihickson 1487: <p class="note">The handling of events or the execution of
1488: callbacks might get prematurely aborted by the "<a href="#kill-a-worker">kill a
1489: worker</a>" or "<a href="#terminate-a-worker">terminate a worker</a>" algorithms
1.81 ihickson 1490: defined below.</p>
1.8 ihickson 1491:
1.81 ihickson 1492: </li>
1.4 ihickson 1493:
1494: <li>
1495:
1.248 ihickson 1496: <p>If the <span>storage mutex</span> is now owned by the worker's
1497: <span>event loop</span>, release it so that it is once again
1498: free.</p>
1499:
1500: </li>
1501:
1502: <li>
1503:
1504: <p>Remove the task just run in the earlier step, if any, from its
1.81 ihickson 1505: <span>task queue</span>.</p>
1.4 ihickson 1506:
1.81 ihickson 1507: </li>
1.4 ihickson 1508:
1509: <li>
1.8 ihickson 1510:
1.81 ihickson 1511: <p>If there are any more events in the <span>event loop</span>'s
1.115 ihickson 1512: <span title="task queue">task queues</span> or if <var title="">worker global scope</var>'s <a href="#dom-workerglobalscope-closing" title="dom-WorkerGlobalScope-closing">closing</a> flag is set
1.81 ihickson 1513: to false, then jump back to the step above labeled <i>event
1514: loop</i>.</p>
1.8 ihickson 1515:
1.81 ihickson 1516: </li>
1.8 ihickson 1517:
1518: <li>
1.71 ihickson 1519:
1.123 ihickson 1520: <p>Empty the <var title="">worker global scope</var>'s <span>list
1521: of active timeouts</span> and its <span>list of active
1522: intervals</span>.</p>
1.50 ihickson 1523:
1.81 ihickson 1524: </li>
1.50 ihickson 1525:
1.247 ihickson 1526: <li>
1527:
1528: <p>Disentangle all the ports in the list of <a href="#the-worker-s-ports">the worker's
1529: ports</a>.</p>
1530:
1531: </li>
1532:
1.123 ihickson 1533: <!-- v2-onclose
1.81 ihickson 1534: <li>
1.50 ihickson 1535:
1.123 ihickson 1536: <p>For each <code>Worker</code> or <code>SharedWorker</code>
1.81 ihickson 1537: object associated with <var title="">worker global scope</var>,
1538: <span>queue a task</span> to <span>fire a simple event</span>
1.179 ihickson 1539: named <code title="event-close">close</code> at that object.</p>
1.5 ihickson 1540:
1.81 ihickson 1541: </li>
1.123 ihickson 1542: -->
1.155 ihickson 1543: </ol><hr><p>When a user agent is to <dfn id="kill-a-worker">kill a worker</dfn> it must
1.81 ihickson 1544: run the following steps in parallel with the worker's main loop (the
1.155 ihickson 1545: "<a href="#run-a-worker">run a worker</a>" processing model defined above):<ol><!-- v2-onclose
1.123 ihickson 1546: <li><p>If the worker's <code>WorkerGlobalScope</code> object's
1547: <span title="dom-WorkerGlobalScope-closing">closing</span> flag is
1.81 ihickson 1548: false, <span>queue a task</span> to <span>fire a simple
1.179 ihickson 1549: event</span> named <code title="event-close">close</code> at the
1.123 ihickson 1550: worker's <code>WorkerGlobalScope</code> object.</p></li>
1.155 ihickson 1551: --><li><p>Set the worker's <code><a href="#workerglobalscope">WorkerGlobalScope</a></code> object's <a href="#dom-workerglobalscope-closing" title="dom-WorkerGlobalScope-closing">closing</a> flag to
1.81 ihickson 1552: true.</li>
1553:
1.123 ihickson 1554: <!-- v2-onclose
1555: <li><p>Wait a user-agent-defined amount of time. If the "<span>run
1556: a worker</span>" processing model defined above immediately starts
1557: running event listeners registered for the <code
1558: title="event-close">close</code> event, this time should not be
1559: zero — the idea is that the <code
1560: title="event-close">close</code> event can be used to clean up
1561: when shutting down unexpectedly.</p></li>
1562: -->
1.81 ihickson 1563:
1.115 ihickson 1564: <li><p>If there are any <span title="concept-task">tasks</span>
1.81 ihickson 1565: queued in the <span>event loop</span>'s <span title="task
1.123 ihickson 1566: queue">task queues</span><!-- v2-onclose other than the <code
1567: title="event-close">close</code> event that this algorithm just
1568: added-->, discard them without processing them.</li>
1.81 ihickson 1569:
1.123 ihickson 1570: <!-- v2-onclose
1.115 ihickson 1571: <li><p>If the <code title="event-close">close</code> event that
1.81 ihickson 1572: this algorithm just queued hasn't yet been dispatched, then abort
1.123 ihickson 1573: the script currently running in the worker.</p></li>
1574: -->
1.81 ihickson 1575:
1576: <li><p>Wait a user-agent-defined amount of time.</li>
1577:
1.123 ihickson 1578: <li><p>Abort the script currently running in the worker<!--
1579: v2-onclose (if any script is running, then it will be a handler for
1580: the <code title="event-close">close</code> event)-->.</li>
1.81 ihickson 1581:
1.155 ihickson 1582: </ol><p>User agents may invoke the "<a href="#kill-a-worker">kill a worker</a>"
1.81 ihickson 1583: processing model on a worker at any time, e.g. in response to user
1584: requests, in response to CPU quota management, or when a worker
1.115 ihickson 1585: stops being an <a href="#active-needed-worker">active needed worker</a> if the worker
1586: continues executing even after its <a href="#dom-workerglobalscope-closing" title="dom-WorkerGlobalScope-closing">closing</a> flag was
1.155 ihickson 1587: set to true.<hr><p>When a user agent is to <dfn id="terminate-a-worker">terminate a worker</dfn> it must run
1.81 ihickson 1588: the following steps in parallel with the worker's main loop (the
1.155 ihickson 1589: "<a href="#run-a-worker">run a worker</a>" processing model defined above):<ol><li><p>Set the worker's <code><a href="#workerglobalscope">WorkerGlobalScope</a></code> object's
1.115 ihickson 1590: <a href="#dom-workerglobalscope-closing" title="dom-WorkerGlobalScope-closing">closing</a> flag to
1.81 ihickson 1591: true.</li>
1592:
1.115 ihickson 1593: <li><p>If there are any <span title="concept-task">tasks</span>
1.81 ihickson 1594: queued in the <span>event loop</span>'s <span title="task
1595: queue">task queues</span>, discard them without processing
1596: them.</li>
1597:
1598: <li><p>Abort the script currently running in the worker.</li>
1599:
1.115 ihickson 1600: <li><p>If the worker's <code><a href="#workerglobalscope">WorkerGlobalScope</a></code> object is
1601: actually a <code><a href="#dedicatedworkerglobalscope">DedicatedWorkerGlobalScope</a></code> object (i.e. the
1.81 ihickson 1602: worker is a dedicated worker), then empty the <span>port message
1603: queue</span> of the port that the worker's implicit port is
1604: entangled with.</li>
1605:
1.155 ihickson 1606: </ol><hr><p>The <span>task source</span> for the tasks mentioned above is the
1.186 ihickson 1607: <span>DOM manipulation task source</span>.<h3 id="runtime-script-errors"><span class="secno">4.6 </span>Runtime script errors</h3><p>Whenever an uncaught runtime script error occurs in one of the
1.143 ihickson 1608: worker's scripts, if the error did not occur while handling a
1609: previous script error, the user agent must <span>report the
1610: error</span> using the <code><a href="#workerglobalscope">WorkerGlobalScope</a></code> object's <code title="handler-WorkerGlobalScope-onerror"><a href="#handler-workerglobalscope-onerror">onerror</a></code>
1.205 ihickson 1611: attribute.
1612:
1.226 ihickson 1613: <a href="#refsHTML">[HTML]</a>
1.205 ihickson 1614:
1615: <p>For shared workers, if the error is still <i title="concept-error-nothandled">not handled</i> afterwards, or if
1.132 ihickson 1616: the error occurred while handling a previous script error, the error
1.215 ihickson 1617: may be reported to the user.
1.205 ihickson 1618:
1.226 ihickson 1619: <a href="#refsHTML">[HTML]</a>
1.205 ihickson 1620:
1621: <p>For dedicated workers, if the error is still <i title="concept-error-nothandled">not handled</i> afterwards, or if
1.132 ihickson 1622: the error occurred while handling a previous script error, the user
1.123 ihickson 1623: agent must <span>queue a task</span> to <a href="#fire-a-worker-error-event">fire a worker error
1624: event</a> at the <code><a href="#worker">Worker</a></code> object associated with the
1.155 ihickson 1625: worker.<p>When the user agent is to <dfn id="fire-a-worker-error-event">fire a worker error event</dfn> at
1.118 ihickson 1626: a <code><a href="#worker">Worker</a></code> object, it must dispatch an event that uses
1627: the <code><a href="#errorevent">ErrorEvent</a></code> interface, with the name <code title="event-error">error</code>, that doesn't bubble and is
1.115 ihickson 1628: cancelable, with its <code title="dom-ErrorEvent-message"><a href="#dom-errorevent-message">message</a></code>, <code title="dom-ErrorEvent-filename"><a href="#dom-errorevent-filename">filename</a></code>, and <code title="dom-ErrorEvent-lineno"><a href="#dom-errorevent-lineno">lineno</a></code> attributes set
1.81 ihickson 1629: appropriately. The default action of this event depends on whether
1.115 ihickson 1630: the <code><a href="#worker">Worker</a></code> object is itself in a worker. If it is, and
1.81 ihickson 1631: that worker is also a dedicated worker, then the user agent must
1.118 ihickson 1632: again <span>queue a task</span> to <a href="#fire-a-worker-error-event">fire a worker error
1633: event</a> at the <code><a href="#worker">Worker</a></code> object associated with
1.215 ihickson 1634: <em>that</em> worker. Otherwise, then the error may be reported
1.155 ihickson 1635: to the user.<p>The <span>task source</span> for the tasks mentioned above is the
1.233 ihickson 1636: <span>DOM manipulation task source</span>.<hr><pre class="idl">interface <dfn id="errorevent">ErrorEvent</dfn> : <span>Event</span> {
1.147 ihickson 1637: readonly attribute DOMString <a href="#dom-errorevent-message" title="dom-ErrorEvent-message">message</a>;
1638: readonly attribute DOMString <a href="#dom-errorevent-filename" title="dom-ErrorEvent-filename">filename</a>;
1.115 ihickson 1639: readonly attribute unsigned long <a href="#dom-errorevent-lineno" title="dom-ErrorEvent-lineno">lineno</a>;
1.147 ihickson 1640: void <a href="#dom-errorevent-initerrorevent" title="dom-ErrorEvent-initErrorEvent">initErrorEvent</a>(in DOMString typeArg, in boolean canBubbleArg, in boolean cancelableArg, in DOMString messageArg, in DOMString filenameArg, in unsigned long linenoArg);
1.155 ihickson 1641: };</pre><p>The <dfn id="dom-errorevent-initerrorevent" title="dom-ErrorEvent-initErrorEvent"><code>initErrorEvent()</code></dfn>
1.190 ihickson 1642: method must initialize the event in a manner analogous to the
1643: similarly-named method in the DOM Events interfaces. <a href="#refsDOMEVENTS">[DOMEVENTS]</a><p>The <dfn id="dom-errorevent-message" title="dom-ErrorEvent-message"><code>message</code></dfn>
1.155 ihickson 1644: attribute represents the error message.<p>The <dfn id="dom-errorevent-filename" title="dom-ErrorEvent-filename"><code>filename</code></dfn>
1.81 ihickson 1645: attribute represents the <span>absolute URL</span> of the script in
1.155 ihickson 1646: which the error originally occurred.<p>The <dfn id="dom-errorevent-lineno" title="dom-ErrorEvent-lineno"><code>lineno</code></dfn>
1.132 ihickson 1647: attribute represents the line number where the error occurred in the
1.208 ihickson 1648: script.<h3 id="creating-workers"><span class="secno">4.7 </span>Creating workers</h3><h4 id="the-abstractworker-abstract-interface"><span class="secno">4.7.1 </span>The <code><a href="#abstractworker">AbstractWorker</a></code> abstract interface</h4><pre class="idl">[Supplemental, NoInterfaceObject]
1649: interface <dfn id="abstractworker">AbstractWorker</dfn> {
1.144 ihickson 1650: attribute <span>Function</span> <a href="#handler-abstractworker-onerror" title="handler-AbstractWorker-onerror">onerror</a>;
1651: <!-- v2-onclose attribute <span>Function</span> <span title="handler-AbstractWorker-onclose">onclose</span>; -->
1.172 ihickson 1652: };
1.177 ihickson 1653: <a href="#abstractworker">AbstractWorker</a> implements <span>EventTarget</span>;</pre><p>The following are the <span>event handlers</span> (and their
1654: corresponding <span title="event handler event type">event handler
1655: event types</span>) that must be supported, as IDL attributes, by
1656: objects implementing the <code><a href="#abstractworker">AbstractWorker</a></code> interface:<table><thead><tr><th><span title="event handlers">Event handler</span> <th><span>Event handler event type</span>
1.155 ihickson 1657: <tbody><tr><td><dfn id="handler-abstractworker-onerror" title="handler-AbstractWorker-onerror"><code>onerror</code></dfn> <td> <code title="event-error">error</code>
1.123 ihickson 1658: <!-- v2-onclose <tr><td><dfn title="handler-AbstractWorker-onclose"><code>onclose</code></dfn> <td> <code title="event-close">close</code> -->
1.186 ihickson 1659: </table><h4 id="dedicated-workers-and-the-worker-interface"><span class="secno">4.7.2 </span>Dedicated workers and the <code><a href="#worker">Worker</a></code> interface</h4><pre class="idl">[<a href="#dom-worker" title="dom-Worker">Constructor</a>(in DOMString scriptURL)]
1.115 ihickson 1660: interface <dfn id="worker">Worker</dfn> : <a href="#abstractworker">AbstractWorker</a> {
1661: void <a href="#dom-worker-terminate" title="dom-Worker-terminate">terminate</a>();
1.50 ihickson 1662:
1.174 ihickson 1663: void <a href="#dom-worker-postmessage" title="dom-Worker-postMessage">postMessage</a>(in any message, in optional <span>MessagePortArray</span> ports);<!--
1.81 ihickson 1664: <span>MessagePort</span> <span title="dom-Worker-startConversation">startConversation</span>(in any message);-->
1.144 ihickson 1665: attribute <span>Function</span> <a href="#handler-worker-onmessage" title="handler-Worker-onmessage">onmessage</a>;
1.155 ihickson 1666: };</pre><p>The <dfn id="dom-worker-terminate" title="dom-Worker-terminate"><code>terminate()</code></dfn> method,
1.115 ihickson 1667: when invoked, must cause the "<a href="#terminate-a-worker">terminate a worker</a>"
1.81 ihickson 1668: algorithm to be run on the worker with with the object is
1.155 ihickson 1669: associated.<p><code><a href="#worker">Worker</a></code> objects act as if they had an implicit
1.81 ihickson 1670: <code>MessagePort</code> associated with them. This port is part of
1671: a channel that is set up when the worker is created, but it is not
1672: exposed. This object must never be garbage collected before the
1.155 ihickson 1673: <code><a href="#worker">Worker</a></code> object.<p>All messages received by that port must immediately be retargeted
1674: at the <code><a href="#worker">Worker</a></code> object.<p>The <dfn id="dom-worker-postmessage" title="dom-Worker-postMessage"><code>postMessage()</code></dfn><!--
1.64 ihickson 1675: and <dfn
1676: title="dom-Worker-startConversation"><code>startConversation()</code></dfn>-->
1.115 ihickson 1677: method<!--s (startConversation)--> on <code><a href="#worker">Worker</a></code> objects
1.81 ihickson 1678: must act as if, when invoked, it<!--/they (startConversation)-->
1679: immediately invoked the method of the same name on the port, with
1.177 ihickson 1680: the same arguments, and returned the same return value.<p>The following are the <span>event handlers</span> (and their
1681: corresponding <span title="event handler event type">event handler
1682: event types</span>) that must be supported, as IDL attributes, by
1683: objects implementing the <code><a href="#worker">Worker</a></code> interface:<table><thead><tr><th><span title="event handlers">Event handler</span> <th><span>Event handler event type</span>
1.155 ihickson 1684: <tbody><tr><td><dfn id="handler-worker-onmessage" title="handler-Worker-onmessage"><code>onmessage</code></dfn> <td> <code title="event-message">message</code>
1685: </table><hr><p>When the <dfn id="dom-worker" title="dom-Worker"><code>Worker(<var title="">scriptURL</var>)</code></dfn> constructor is invoked, the
1.216 ihickson 1686: user agent must run the following steps:<ol><li><p><span title="resolve a url">Resolve</span> the <var title="">scriptURL</var> argument relative to the <span>entry
1.133 ihickson 1687: script</span>'s <span title="script's base URL">base URL</span>,
1688: when the method is invoked.</li>
1.9 ihickson 1689:
1.81 ihickson 1690: <li><p>If this fails, throw a <code>SYNTAX_ERR</code>
1691: exception.</li>
1.9 ihickson 1692:
1.167 ihickson 1693: <li>
1694:
1695: <p>If the <span>origin</span> of the resulting <span>absolute
1696: URL</span> is not the <span title="same origin">same</span> as the
1.216 ihickson 1697: origin of the <span>entry script</span>, then throw a
1.182 ihickson 1698: <code>SECURITY_ERR</code> exception.</p>
1.167 ihickson 1699:
1700: <p class="note">Thus, scripts must be external files with the same
1.269 ihickson 1701: scheme as the original page: you can't load a script from a <span title="data protocol"><code title="">data:</code> URL</span> or
1702: <span title="javascript protocol"><code title="">javascript:</code> URL</span>, and an <code>http:</code>
1703: page couldn't start workers using scripts with <code>http:</code>
1704: URLs.</p>
1.167 ihickson 1705:
1706: </li>
1.9 ihickson 1707:
1.185 ihickson 1708: <li><p>Create a new <code><a href="#dedicatedworkerglobalscope">DedicatedWorkerGlobalScope</a></code>
1709: object. Let <var title="">worker global scope</var> be this new
1710: object.</li>
1.9 ihickson 1711:
1.115 ihickson 1712: <li><p>Create a new <code><a href="#worker">Worker</a></code> object, associated with
1.81 ihickson 1713: <var title="">worker global scope</var>. Let <var title="">worker</var> be this new object.</li>
1.50 ihickson 1714:
1.185 ihickson 1715: <li><p><span>Create a new <code>MessagePort</code> object</span>
1.192 ihickson 1716: owned by the <span title="script's global object">global
1717: object</span> of the <span title="concept-script">script</span> that
1.185 ihickson 1718: invoked the constructor. Let this be the <var title="">outside
1.81 ihickson 1719: port</var>.</li>
1.9 ihickson 1720:
1.81 ihickson 1721: <li><p>Associate the <var title="">outside port</var> with <var title="">worker</var>.</li>
1.50 ihickson 1722:
1.185 ihickson 1723: <li><p><span>Create a new <code>MessagePort</code> object</span>
1724: owned by <var title="">worker global scope</var>. Let <var title="">inside port</var> be this new object.</li>
1.50 ihickson 1725:
1.81 ihickson 1726: <li><p>Associate <var title="">inside port</var> with <var title="">worker global scope</var>.</li>
1.50 ihickson 1727:
1.81 ihickson 1728: <li><p><span>Entangle</span> <var title="">outside port</var> and
1729: <var title="">inside port</var>.</li>
1.50 ihickson 1730:
1.81 ihickson 1731: <li><p>Return <var title="">worker</var>, and run the following
1732: steps asynchronously.</li>
1.50 ihickson 1733:
1.204 ihickson 1734: <!-- (this is done by the "run a worker" algorithm)
1.126 ihickson 1735: <li><p>Enable <var title="">inside port</var>'s <span>port message
1.204 ihickson 1736: queue</span>.</p></li>
1737: -->
1.50 ihickson 1738:
1.126 ihickson 1739: <li><p>Enable <var title="">outside port</var>'s <span>port message
1.81 ihickson 1740: queue</span>.</li>
1.50 ihickson 1741:
1742: <li>
1.51 ihickson 1743:
1.123 ihickson 1744: <p>Let <var title="">docs</var> be the <a href="#list-of-relevant-document-objects-to-add">list of relevant
1.192 ihickson 1745: <code>Document</code> objects to add</a> given the <span title="script's global object">global object</span> of the <span title="concept-script">script</span> that invoked the
1.123 ihickson 1746: constructor.</p>
1747:
1748: </li>
1749:
1750: <li>
1751:
1752: <p><a href="#add-a-document-to-the-worker-s-documents" title="add a document to the worker's documents">Add to
1753: <var title="">worker global scope</var>'s list of <span>the
1754: worker's <code>Document</code>s</span></a> the
1755: <code>Document</code> objects in <var title="">docs</var>.</p>
1756:
1757: </li>
1758:
1759: <li>
1760:
1.192 ihickson 1761: <p>If the <span title="script's global object">global object</span>
1.124 ihickson 1762: of the <span title="concept-script">script</span> that invoked the
1763: constructor is a <code><a href="#workerglobalscope">WorkerGlobalScope</a></code> object (i.e. we
1764: are creating a nested worker), add <var title="">worker global
1765: scope</var> to the list of <a href="#the-worker-s-workers">the worker's workers</a> of the
1.192 ihickson 1766: <code><a href="#workerglobalscope">WorkerGlobalScope</a></code> object that is the <span title="script's global object">global object</span> of the <span title="concept-script">script</span> that invoked the
1.124 ihickson 1767: constructor.</p>
1768:
1769: </li>
1770:
1771: <li>
1772:
1.115 ihickson 1773: <p><a href="#run-a-worker">Run a worker</a> for the resulting <span>absolute
1.193 ihickson 1774: URL</span>, with the <span>script's browsing context</span> of the
1.81 ihickson 1775: script that invoked the method as the <var title="">owner browsing
1.232 ihickson 1776: context</var>, with the <span>script's document</span> of the
1777: script that invoked the method as the <var title="">owner
1778: document</var>, with the <span>origin</span> of the <span>entry
1.176 ihickson 1779: script</span> as the <var title="">owner origin</var>, and with
1780: <var title="">worker global scope</var> as the global scope.</p>
1.9 ihickson 1781:
1.81 ihickson 1782: </li>
1.4 ihickson 1783:
1.155 ihickson 1784: </ol><p>This constructor must be visible when the <span>script's global
1.192 ihickson 1785: object</span> is either a <code>Window</code> object or an object
1.186 ihickson 1786: implementing the <code><a href="#workerutils">WorkerUtils</a></code> interface.<h4 id="shared-workers-and-the-sharedworker-interface"><span class="secno">4.7.3 </span>Shared workers and the <code><a href="#sharedworker">SharedWorker</a></code> interface</h4><pre class="idl">[<a href="#dom-sharedworker" title="dom-SharedWorker">Constructor</a>(in DOMString scriptURL, in optional DOMString name)]
1.115 ihickson 1787: interface <dfn id="sharedworker">SharedWorker</dfn> : <a href="#abstractworker">AbstractWorker</a> {
1788: readonly attribute <span>MessagePort</span> <a href="#dom-sharedworker-port" title="dom-SharedWorker-port">port</a>;
1.155 ihickson 1789: };</pre><p>The <dfn id="dom-sharedworker-port" title="dom-SharedWorker-port"><code>port</code></dfn>
1.81 ihickson 1790: attribute must return the value it was assigned by the object's
1791: constructor. It represents the <code>MessagePort</code> for
1.155 ihickson 1792: communicating with the shared worker.<p>When the <dfn id="dom-sharedworker" title="dom-SharedWorker"><code>SharedWorker(<var title="">scriptURL</var>, <var title="">name</var>)</code></dfn>
1.81 ihickson 1793: constructor is invoked, the user agent must run the following
1.155 ihickson 1794: steps:<ol><li><p><span title="resolve a url">Resolve</span> the <var title="">scriptURL</var> argument.</li>
1.81 ihickson 1795:
1796: <li><p>If this fails, throw a <code>SYNTAX_ERR</code>
1797: exception.</li>
1798:
1.159 ihickson 1799: <li><p>Otherwise, let <var title="">scriptURL</var> be the
1800: resulting <span>absolute URL</span>.</li>
1801:
1802: <li><p>Let <var title="">name</var> be the value of the second
1.164 ihickson 1803: argument, or the empty string if the second argument was
1804: omitted.</li>
1.159 ihickson 1805:
1.167 ihickson 1806: <li>
1807:
1808: <p>If the <span>origin</span> of <var title="">scriptURL</var> is
1809: not the <span title="same origin">same</span> as the origin of the
1.216 ihickson 1810: <span>entry script</span>, then throw a <code>SECURITY_ERR</code>
1.182 ihickson 1811: exception.</p>
1.167 ihickson 1812:
1813: <p class="note">Thus, scripts must be external files with the same
1.269 ihickson 1814: scheme as the original page: you can't load a script from a <span title="data protocol"><code title="">data:</code> URL</span> or
1815: <span title="javascript protocol"><code title="">javascript:</code> URL</span>, and a <code>http:</code>
1816: page couldn't start workers using scripts with <code>http:</code>
1817: URLs.</p>
1.167 ihickson 1818:
1819: </li>
1.9 ihickson 1820:
1821: <li>
1822:
1.123 ihickson 1823: <p>Let <var title="">docs</var> be the <a href="#list-of-relevant-document-objects-to-add">list of relevant
1.192 ihickson 1824: <code>Document</code> objects to add</a> given the <span title="script's global object">global object</span> of the <span title="concept-script">script</span> that invoked the
1.123 ihickson 1825: constructor.</p>
1826:
1827: </li>
1828:
1829: <li>
1830:
1.50 ihickson 1831: <p>Execute the following substeps atomically:</p>
1.9 ihickson 1832:
1.155 ihickson 1833: <ol><li><p>Create a new <code><a href="#sharedworker">SharedWorker</a></code> object, which will
1.115 ihickson 1834: shortly be associated with a <code><a href="#sharedworkerglobalscope">SharedWorkerGlobalScope</a></code>
1835: object. Let this <code><a href="#sharedworker">SharedWorker</a></code> object be <var title="">worker</var>.</li>
1.81 ihickson 1836:
1.185 ihickson 1837: <li><p><span>Create a new <code>MessagePort</code> object</span>
1.192 ihickson 1838: owned by the <span title="script's global object">global
1839: object</span> of the script that invoked the method. Let this be
1.123 ihickson 1840: the <var title="">outside port</var>.</li>
1.81 ihickson 1841:
1.115 ihickson 1842: <li><p>Assign <var title="">outside port</var> to the <code title="dom-SharedWorker-port"><a href="#dom-sharedworker-port">port</a></code> attribute of <var title="">worker</var>.</li>
1.81 ihickson 1843:
1.164 ihickson 1844: <li><p>Let <var title="">worker global scope</var> be
1845: null.</li>
1846:
1847: <li><p>If <var title="">name</var> is not the empty string and
1848: there exists a <code><a href="#sharedworkerglobalscope">SharedWorkerGlobalScope</a></code> object whose
1849: <a href="#dom-workerglobalscope-closing" title="dom-WorkerGlobalScope-closing">closing</a> flag
1850: is false, whose <code title="dom-WorkerGlobalScope-name">name</code> attribute is
1851: exactly equal to <var title="">name</var>, and whose <code title="dom-WorkerGlobalScope-location"><a href="#dom-workerglobalscope-location">location</a></code> attribute
1852: represents an <span>absolute URL</span> with the <span>same
1853: origin</span> as <var title="">scriptURL</var>, then let <var title="">worker global scope</var> be that
1854: <code><a href="#sharedworkerglobalscope">SharedWorkerGlobalScope</a></code> object.</li>
1855:
1856: <li><p>Otherwise, if <var title="">name</var> is the empty string
1857: and there exists a <code><a href="#sharedworkerglobalscope">SharedWorkerGlobalScope</a></code> object
1858: whose <a href="#dom-workerglobalscope-closing" title="dom-WorkerGlobalScope-closing">closing</a>
1859: flag is false, and whose <code title="dom-WorkerGlobalScope-location"><a href="#dom-workerglobalscope-location">location</a></code> attribute
1.237 ihickson 1860: represents an <span>absolute URL</span> that is exactly equal to
1861: <var title="">scriptURL</var>, then let <var title="">worker
1862: global scope</var> be that <code><a href="#sharedworkerglobalscope">SharedWorkerGlobalScope</a></code>
1863: object.</li>
1.164 ihickson 1864:
1.9 ihickson 1865: <li>
1866:
1.164 ihickson 1867: <p>If <var title="">worker global scope</var> is not null, then
1868: run these steps:</p>
1.81 ihickson 1869:
1.164 ihickson 1870: <ol><li><p>If <var title="">worker global scope</var>'s <code title="dom-WorkerGlobalScope-location"><a href="#dom-workerglobalscope-location">location</a></code>
1.81 ihickson 1871: attribute represents an <span>absolute URL</span> that is not
1.159 ihickson 1872: exactly equal to <var title="">scriptURL</var>, then throw a
1873: <code>URL_MISMATCH_ERR</code> exception and abort all these
1874: steps.</li>
1.81 ihickson 1875:
1876: <li><p>Associate <var title="">worker</var> with <var title="">worker global scope</var>.</li>
1877:
1.185 ihickson 1878: <li><p><span>Create a new <code>MessagePort</code>
1879: object</span> owned by <var title="">worker global
1880: scope</var>. Let this be the <var title="">inside
1881: port</var>.</li>
1.81 ihickson 1882:
1883: <li><p><span>Entangle</span> <var title="">outside port</var>
1884: and <var title="">inside port</var>.</li>
1885:
1886: <li><p>Return <var title="">worker</var> and perform the next
1887: step asynchronously.</li>
1.9 ihickson 1888:
1.81 ihickson 1889: <li><p>Create an event that uses the <code>MessageEvent</code>
1.115 ihickson 1890: interface, with the name <code title="event-connect">connect</code>, which does not bubble, is
1.118 ihickson 1891: not cancelable, has no default action, has a <code title="dom-MessageEvent-data">data</code> attribute whose value
1892: is the empty string and has a <code title="dom-MessageEvent-ports">ports</code> attribute whose
1893: value is an array containing only the newly created port, and
1894: <span>queue a task</span> to dispatch the event at <var title="">worker global scope</var>.</li>
1.43 ihickson 1895:
1.123 ihickson 1896: <li>
1897:
1898: <p><a href="#add-a-document-to-the-worker-s-documents" title="add a document to the worker's documents">Add to
1899: <var title="">worker global scope</var>'s list of <span>the
1900: worker's <code>Document</code>s</span></a> the
1901: <code>Document</code> objects in <var title="">docs</var>.</p>
1902:
1903: </li>
1904:
1.124 ihickson 1905: <li>
1906:
1.192 ihickson 1907: <p>If the <span title="script's global object">global
1908: object</span> of the <span title="concept-script">script</span>
1.124 ihickson 1909: that invoked the constructor is a
1910: <code><a href="#workerglobalscope">WorkerGlobalScope</a></code> object, add <var title="">worker global scope</var> to the list of <a href="#the-worker-s-workers">the
1911: worker's workers</a> of the <code><a href="#workerglobalscope">WorkerGlobalScope</a></code>
1.192 ihickson 1912: object that is the <span title="script's global object">global
1913: object</span> of the <span title="concept-script">script</span>
1.124 ihickson 1914: that invoked the constructor.</p>
1915:
1916: </li>
1917:
1.81 ihickson 1918: <li><p>Abort all these steps.</li>
1.9 ihickson 1919:
1.155 ihickson 1920: </ol></li>
1.9 ihickson 1921:
1.185 ihickson 1922: <li><p>Create a new <code><a href="#sharedworkerglobalscope">SharedWorkerGlobalScope</a></code>
1923: object. Let <var title="">worker global scope</var> be this new
1924: object.</li>
1.9 ihickson 1925:
1.81 ihickson 1926: <li><p>Associate <var title="">worker</var> with <var title="">worker global scope</var>.</li>
1.9 ihickson 1927:
1.115 ihickson 1928: <li><p>Set the <code title="dom-SharedWorkerGlobalScope-name"><a href="#dom-sharedworkerglobalscope-name">name</a></code> attribute of
1.81 ihickson 1929: <var title="">worker global scope</var> to <var title="">name</var>.</li>
1.9 ihickson 1930:
1.185 ihickson 1931: <li><p><span>Create a new <code>MessagePort</code> object</span>
1.81 ihickson 1932: owned by <var title="">worker global scope</var>. Let <var title="">inside port</var> be this new object.</li>
1.9 ihickson 1933:
1.81 ihickson 1934: <li><p><span>Entangle</span> <var title="">outside port</var> and
1935: <var title="">inside port</var>.</li>
1.9 ihickson 1936:
1.155 ihickson 1937: </ol></li>
1.28 ihickson 1938:
1.123 ihickson 1939: <li><p>Return <var title="">worker</var> and perform the remaining
1940: steps asynchronously.</li>
1.18 ihickson 1941:
1.81 ihickson 1942: <li><p>Create an event that uses the <code>MessageEvent</code>
1.118 ihickson 1943: interface, with the name <code title="event-connect">connect</code>, which does not bubble, is not
1.115 ihickson 1944: cancelable, has no default action, has a <code title="dom-MessageEvent-data">data</code> attribute whose value is
1.118 ihickson 1945: the empty string and has a <code title="dom-MessageEvent-ports">ports</code> attribute whose value
1946: is an array containing only the newly created port, and <span>queue
1947: a task</span> to dispatch the event at <var title="">worker global
1948: scope</var>.</li>
1.26 ihickson 1949:
1950: <li>
1.46 ihickson 1951:
1.123 ihickson 1952: <p><a href="#add-a-document-to-the-worker-s-documents" title="add a document to the worker's documents">Add to
1953: <var title="">worker global scope</var>'s list of <span>the
1954: worker's <code>Document</code>s</span></a> the
1955: <code>Document</code> objects in <var title="">docs</var>.</p>
1956:
1957: </li>
1958:
1959: <li>
1960:
1.192 ihickson 1961: <p>If the <span title="script's global object">global object</span>
1.124 ihickson 1962: of the <span title="concept-script">script</span> that invoked the
1963: constructor is a <code><a href="#workerglobalscope">WorkerGlobalScope</a></code> object, add <var title="">worker global scope</var> to the list of <a href="#the-worker-s-workers">the
1964: worker's workers</a> of the <code><a href="#workerglobalscope">WorkerGlobalScope</a></code>
1.192 ihickson 1965: object that is the <span title="script's global object">global
1966: object</span> of the <span title="concept-script">script</span>
1.124 ihickson 1967: that invoked the constructor.</p>
1968:
1969: </li>
1970:
1971: <li>
1972:
1.159 ihickson 1973: <p><a href="#run-a-worker">Run a worker</a> for <var title="">scriptURL</var>,
1.193 ihickson 1974: with the <span>script's browsing context</span> of the script that
1.159 ihickson 1975: invoked the method as the <var title="">owner browsing
1.232 ihickson 1976: context</var>, with the <span>script's document</span> of the
1977: script that invoked the method as the <var title="">owner
1978: document</var>, with the <span>origin</span> of the <span>entry
1.176 ihickson 1979: script</span> as the <var title="">owner origin</var>, and with
1980: <var title="">worker global scope</var> as the global scope.</p>
1.26 ihickson 1981:
1.60 ihickson 1982: </li>
1.81 ihickson 1983:
1.155 ihickson 1984: </ol><p>This constructor must be visible when the <span>script's global
1.192 ihickson 1985: object</span> is either a <code>Window</code> object or an object
1.155 ihickson 1986: implementing the <code><a href="#workerutils">WorkerUtils</a></code> interface.<p>The <span>task source</span> for the tasks mentioned above is the
1987: <span>DOM manipulation task source</span>.<h2 id="apis-available-to-workers"><span class="secno">5 </span>APIs available to workers</h2><pre class="idl">[Supplemental, NoInterfaceObject]
1.150 ihickson 1988: interface <dfn id="workerutils">WorkerUtils</dfn> {
1989: void <a href="#dom-workerglobalscope-importscripts" title="dom-WorkerGlobalScope-importScripts">importScripts</a>(in DOMString... urls);
1.210 ihickson 1990: readonly attribute <a href="#workernavigator">WorkerNavigator</a> <a href="#dom-worker-navigator" title="dom-worker-navigator">navigator</a>;
1.150 ihickson 1991: };
1.184 ihickson 1992: <a href="#workerutils">WorkerUtils</a> implements <span>WindowTimers</span>;</pre><p>The DOM APIs (<code>Node</code> objects, <code>Document</code>
1.81 ihickson 1993: objects, etc) are not available to workers in this version of this
1.155 ihickson 1994: specification.<h3 id="importing-scripts-and-libraries"><span class="secno">5.1 </span>Importing scripts and libraries</h3><p>When a script invokes the <dfn id="dom-workerglobalscope-importscripts" title="dom-WorkerGlobalScope-importScripts"><code>importScripts(<var title="">urls</var>)</code></dfn> method on a
1.115 ihickson 1995: <code><a href="#workerglobalscope">WorkerGlobalScope</a></code> object, the user agent must run the
1.155 ihickson 1996: following steps:<ol><li><p>If there are no arguments, return without doing
1.81 ihickson 1997: anything. Abort these steps.</li>
1998:
1999: <li><p><span title="resolve a url">Resolve</span> each
2000: argument.</li>
2001:
2002: <li><p>If any fail, throw a <code>SYNTAX_ERR</code>
2003: exception.</li>
2004:
2005: <!--
1.67 ihickson 2006: <li><p>If any of the resulting <span title="absolute URL">absolute
2007: URLs</span> have an <span>origin</span> that is not the <span
2008: title="same origin">same</span> as the origin of the script that
1.182 ihickson 2009: invoked the method, then throw a <code>SECURITY_ERR</code>
2010: exception.</p></li>
1.67 ihickson 2011: -->
1.26 ihickson 2012:
2013: <li>
1.81 ihickson 2014:
1.45 ihickson 2015: <p>Attempt to <span>fetch</span> each resource identified by the
1.194 ihickson 2016: resulting <span title="absolute URL">absolute URLs</span>, from
1.256 ihickson 2017: the <span>entry script</span>'s <span>origin</span>, with the
2018: <i>synchronous flag</i> set.</p> <!-- not http-origin privacy
2019: sensitive -->
1.81 ihickson 2020:
2021: </li>
1.26 ihickson 2022:
2023: <li>
2024:
1.81 ihickson 2025: <p>For each argument in turn, in the order given, starting with
2026: the first one, run these substeps:</p>
1.26 ihickson 2027:
1.155 ihickson 2028: <ol><li>
1.26 ihickson 2029:
1.81 ihickson 2030: <p>Wait for the fetching attempt for the corresponding resource
2031: to complete.</p>
1.60 ihickson 2032:
1.81 ihickson 2033: <p>If the fetching attempt failed, throw a
2034: <code>NETWORK_ERR</code> exception and abort all these
2035: steps.</p>
1.45 ihickson 2036:
1.264 ihickson 2037: <p>If the attempt succeeds, then let <var title="">source</var> be
2038: the script resource <span>decoded as UTF-8, with error
2039: handling</span>.
2040:
2041: <a href="#refsHTML">[HTML]</a>
2042:
2043: </p>
1.85 ihickson 2044:
2045: <p>Let <var title="">language</var> be JavaScript.</p>
1.61 ihickson 2046:
1.115 ihickson 2047: <p class="note">As with the worker's script, the script here is
1.81 ihickson 2048: always assumed to be JavaScript, regardless of the MIME
1.170 ihickson 2049: type.</p>
1.61 ihickson 2050:
1.81 ihickson 2051: </li>
1.26 ihickson 2052:
1.81 ihickson 2053: <li>
1.26 ihickson 2054:
1.81 ihickson 2055: <p><span>Create a script</span>, using <var title="">source</var> as the script source and <var title="">language</var> as the scripting language, using the
1.189 ihickson 2056: same global object, browsing context, URL character encoding,
2057: base URL, and script group as the <span title="concept-script">script</span> that was created by the
1.115 ihickson 2058: worker's <a href="#run-a-worker">run a worker</a> algorithm.</p>
1.81 ihickson 2059:
1.115 ihickson 2060: <p>Let the newly created <span title="concept-script">script</span> run until it either
1.81 ihickson 2061: returns, fails to parse, fails to catch an exception, or gets
1.115 ihickson 2062: prematurely aborted by the "<a href="#kill-a-worker">kill a worker</a>" or
2063: "<a href="#terminate-a-worker">terminate a worker</a>" algorithms defined above.</p>
1.26 ihickson 2064:
1.199 ihickson 2065: <p>If it failed to parse, then throw an ECMAScript
2066: <code>SyntaxError</code> exception and abort all these
2067: steps. <a href="#refsECMA262">[ECMA262]</a></p>
1.63 ihickson 2068:
1.81 ihickson 2069: <p>If an exception was raised or if the script was prematurely
2070: aborted, then abort all these steps, letting the exception or
2071: aborting continue to be processed by the script that called the
1.115 ihickson 2072: <code title="dom-WorkerGlobalScope-importScripts"><a href="#dom-workerglobalscope-importscripts">importScripts()</a></code>
1.81 ihickson 2073: method.</p>
2074:
1.115 ihickson 2075: <p>If the "<a href="#kill-a-worker">kill a worker</a>" or "<a href="#terminate-a-worker">terminate a
1.81 ihickson 2076: worker</a>" algorithms abort the script then abort all these
2077: steps.</p>
2078:
2079: </li>
2080:
1.155 ihickson 2081: </ol></li>
1.152 ihickson 2082:
1.210 ihickson 2083: </ol><h3 id="the-workernavigator-object"><span class="secno">5.2 </span>The <code><a href="#workernavigator">WorkerNavigator</a></code> object</h3><p>The <dfn id="dom-worker-navigator" title="dom-worker-navigator"><code>navigator</code></dfn> attribute
1.115 ihickson 2084: of the <code><a href="#workerutils">WorkerUtils</a></code> interface must return an instance of
1.210 ihickson 2085: the <code><a href="#workernavigator">WorkerNavigator</a></code> interface, which represents the
2086: identity and state of the user agent (the client):<pre class="idl">interface <dfn id="workernavigator">WorkerNavigator</dfn> {};
2087: <a href="#workernavigator">WorkerNavigator</a> implements <span>NavigatorID</span>;
2088: <a href="#workernavigator">WorkerNavigator</a> implements <span>NavigatorOnLine</span>;</pre><p>Objects implementing the <code><a href="#workernavigator">WorkerNavigator</a></code> interface
2089: also implement the <code>NavigatorID</code> and
2090: <code>NavigatorOnLine</code> interfaces.
1.205 ihickson 2091:
1.226 ihickson 2092: <a href="#refsHTML">[HTML]</a>
1.205 ihickson 2093:
1.210 ihickson 2094: <p>This <code><a href="#workernavigator">WorkerNavigator</a></code> interface must not exist if the
2095: interface's <span>relevant namespace object</span> is a
1.272 ihickson 2096: <code>Window</code> object. <a href="#refsWEBIDL">[WEBIDL]</a><h3 id="interface-objects-and-constructors"><span class="secno">5.3 </span>Interface objects and constructors</h3><p>There must be no interface objects and constructors available in
1.192 ihickson 2097: the global scope of scripts whose <span>script's global
2098: object</span> is a <code><a href="#workerglobalscope">WorkerGlobalScope</a></code> object except for
1.155 ihickson 2099: the following:<ul><li><p><code>XMLHttpRequest</code> and all interface objects and
1.81 ihickson 2100: constructors defined by the XMLHttpRequest specifications, except
2101: that the <span>document response entity body</span> must always be
1.160 ihickson 2102: null. The <span><code>XMLHttpRequest</code> base URL</span> is the
2103: <span>script's base URL</span>; the
2104: <span><code>XMLHttpRequest</code> origin</span> is the script's
2105: <span>origin</span>. <a href="#refsXHR">[XHR]</a></li>
1.81 ihickson 2106:
1.205 ihickson 2107: <li><p>The interface objects and constructors defined by this
2108: specification.</li>
1.119 ihickson 2109:
1.205 ihickson 2110: <li><p>Constructors defined by specifications that explicitly say
2111: that they should be visible when the <span>script's global
2112: object</span> is a <code><a href="#dedicatedworkerglobalscope">DedicatedWorkerGlobalScope</a></code>, a
2113: <code><a href="#sharedworkerglobalscope">SharedWorkerGlobalScope</a></code>, or an object implementing the
2114: <code><a href="#workerutils">WorkerUtils</a></code> interface; the interfaces of any objects
2115: with such constructors; and the interfaces of any objects made
2116: accessible through APIs exposed by those constructors or made
2117: accessible through interfaces to be implemented by any objects that
2118: are themselves accessible to scripts whose <span>script's global
2119: object</span> implements the <code><a href="#workerutils">WorkerUtils</a></code>
2120: interface.</li>
2121:
2122: </ul><p class="note">These requirements do not override the requirements
2123: defined by the Web IDL specification, in particular concerning the
1.272 ihickson 2124: visibility of interfaces annotated with the <code title="">[NoInterfaceObject]</code> extended attribute.<h3 id="worker-locations"><span class="secno">5.4 </span>Worker locations</h3><pre class="idl">interface <dfn id="workerlocation">WorkerLocation</dfn> {
1.263 ihickson 2125: // <span>URL decomposition IDL attributes</span>
1.115 ihickson 2126: readonly attribute DOMString <a href="#dom-workerlocation-href" title="dom-WorkerLocation-href">href</a>;
2127: readonly attribute DOMString <a href="#dom-workerlocation-protocol" title="dom-WorkerLocation-protocol">protocol</a>;
2128: readonly attribute DOMString <a href="#dom-workerlocation-host" title="dom-WorkerLocation-host">host</a>;
2129: readonly attribute DOMString <a href="#dom-workerlocation-hostname" title="dom-WorkerLocation-hostname">hostname</a>;
2130: readonly attribute DOMString <a href="#dom-workerlocation-port" title="dom-WorkerLocation-port">port</a>;
2131: readonly attribute DOMString <a href="#dom-workerlocation-pathname" title="dom-WorkerLocation-pathname">pathname</a>;
2132: readonly attribute DOMString <a href="#dom-workerlocation-search" title="dom-WorkerLocation-search">search</a>;
2133: readonly attribute DOMString <a href="#dom-workerlocation-hash" title="dom-WorkerLocation-hash">hash</a>;
1.155 ihickson 2134: };</pre><p>A <code><a href="#workerlocation">WorkerLocation</a></code> object represents an <span>absolute
2135: URL</span> set at its creation.<p>The <dfn id="dom-workerlocation-href" title="dom-WorkerLocation-href"><code>href</code></dfn>
1.81 ihickson 2136: attribute must return the <span>absolute URL</span> that the object
1.155 ihickson 2137: represents.<p>The <code><a href="#workerlocation">WorkerLocation</a></code> interface also has the complement
1.163 ihickson 2138: of <span>URL decomposition IDL attributes</span>, <dfn id="dom-workerlocation-protocol" title="dom-WorkerLocation-protocol"><code>protocol</code></dfn>,
1.115 ihickson 2139: <dfn id="dom-workerlocation-host" title="dom-WorkerLocation-host"><code>host</code></dfn>, <dfn id="dom-workerlocation-port" title="dom-WorkerLocation-port"><code>port</code></dfn>, <dfn id="dom-workerlocation-hostname" title="dom-WorkerLocation-hostname"><code>hostname</code></dfn>,
2140: <dfn id="dom-workerlocation-pathname" title="dom-WorkerLocation-pathname"><code>pathname</code></dfn>,
2141: <dfn id="dom-workerlocation-search" title="dom-WorkerLocation-search"><code>search</code></dfn>,
1.263 ihickson 2142: and <dfn id="dom-workerlocation-hash" title="dom-WorkerLocation-hash"><code>hash</code></dfn>.
2143: These must follow the rules given for <span>URL decomposition IDL
2144: attributes</span>, with the <span title="concept-uda-input">input</span> being the <span>absolute
2145: URL</span> that the object represents (same as the <code title="dom-WorkerLocation-href"><a href="#dom-workerlocation-href">href</a></code> attribute), and the
2146: <span title="concept-uda-setter">common setter action</span> being a
2147: no-op, since the attributes are defined to be readonly.
1.205 ihickson 2148:
1.226 ihickson 2149: <a href="#refsHTML">[HTML]</a>
1.205 ihickson 2150:
1.209 ihickson 2151: <p>The <code><a href="#workerlocation">WorkerLocation</a></code> interface must not exist if the
2152: interface's <span>relevant namespace object</span> is a
1.251 ihickson 2153: <code>Window</code> object. <a href="#refsWEBIDL">[WEBIDL]</a><h2 class="no-num" id="references">References</h2><!--REFS--><p>All references are normative unless marked "Non-normative".</p><!-- Dates are only included for standards older than the Web, because the newer ones keep changing. --><dl><dt id="refsDOMCORE">[DOMCORE]</dt>
1.153 ihickson 2154: <dd><cite><a href="http://www.w3.org/TR/DOM-Level-3-Core/">Document
2155: Object Model (DOM) Level 3 Core Specification</a></cite>, A. Le
2156: Hors, P. Le Hegaret, L. Wood, G. Nicol, J. Robie, M. Champion,
1.226 ihickson 2157: S. Byrnes. W3C.</dd>
1.153 ihickson 2158: <!--
2159: <dd><cite><a href="http://simon.html5.org/specs/web-dom-core">Web
1.226 ihickson 2160: DOM Core</a></cite>, S. Pieters. W3C.</dd>
1.153 ihickson 2161: -->
2162:
1.152 ihickson 2163: <dt id="refsDOMEVENTS">[DOMEVENTS]</dt>
2164: <!--
2165: <dd><cite><a
2166: href="http://www.w3.org/TR/DOM-Level-3-Events/">Document Object
2167: Model (DOM) Level 3 Events Specification</a></cite>,
1.226 ihickson 2168: B. Höhrmann, P. Le Hegaret, T. Pixley. W3C.</dd>
1.152 ihickson 2169: -->
2170: <dd><cite><a href="http://dev.w3.org/2006/webapi/DOM-Level-3-Events/html/DOM3-Events.html">Document
2171: Object Model (DOM) Level 3 Events Specification</a></cite>,
1.226 ihickson 2172: D. Schepers. W3C.</dd>
1.152 ihickson 2173:
2174: <dt id="refsECMA262">[ECMA262]</dt>
2175: <dd><cite><a href="http://www.ecma-international.org/publications/standards/Ecma-262.htm">ECMAScript
1.226 ihickson 2176: Language Specification</a></cite>. ECMA.</dd>
1.152 ihickson 2177:
1.226 ihickson 2178: <dt id="refsHTML">[HTML]</dt>
2179: <dd><cite><a href="http://www.whatwg.org/specs/web-apps/current-work/">HTML</a></cite>,
2180: I. Hickson. WHATWG.</dd>
1.152 ihickson 2181:
1.154 ihickson 2182: <dt id="refsRFC2119">[RFC2119]</dt>
1.265 ihickson 2183: <dd><cite><a href="http://tools.ietf.org/html/rfc2119">Key words for use in
1.226 ihickson 2184: RFCs to Indicate Requirement Levels</a></cite>, S. Bradner. IETF.</dd>
1.154 ihickson 2185:
2186: <dt id="refsWEBIDL">[WEBIDL]</dt>
2187: <!--
2188: <dd><cite><a href="http://www.w3.org/TR/WebIDL/">Web
1.226 ihickson 2189: IDL</a></cite>, C. McCormack. W3C.</dd>
1.154 ihickson 2190: -->
2191: <dd><cite><a href="http://dev.w3.org/2006/webapi/WebIDL/">Web
1.226 ihickson 2192: IDL</a></cite>, C. McCormack. W3C.</dd>
1.154 ihickson 2193:
1.152 ihickson 2194: <dt id="refsXHR">[XHR]</dt>
2195: <!--
2196: <dd><cite><a href="http://www.w3.org/TR/XMLHttpRequest/">The XMLHttpRequest
1.226 ihickson 2197: Object</a></cite>, A. van Kesteren. W3C.</dd>
1.152 ihickson 2198: -->
1.160 ihickson 2199: <dd><cite><a href="http://dev.w3.org/2006/webapi/XMLHttpRequest-2/"><code>XMLHttpRequest</code></a></cite>,
1.226 ihickson 2200: A. van Kesteren. W3C.</dd>
1.152 ihickson 2201:
1.221 ihickson 2202: </dl><h2 class="no-num" id="acknowledgements">Acknowledgements</h2><!-- ACKS --><p>Thanks to
1.81 ihickson 2203:
2204: Aaron Boodman,
1.155 ihickson 2205: Алексей Проскуряков (Alexey Proskuryakov),
1.81 ihickson 2206: Anne van Kesteren,
2207: Ben Turner,
2208: Dmitry Titov,
1.96 ihickson 2209: Drew Wilson,
1.97 ihickson 2210: Jeremy Orlow,
1.81 ihickson 2211: Jonas Sicking,
2212: Justin James,
2213: Kevin Hakanson,
2214: Maciej Stachowiak,
2215: Michael Nordman,
2216: Mike Smith,
2217:
2218: and
2219:
2220: Philip Taylor
2221:
1.155 ihickson 2222: for their useful and substantial comments.<p>Huge thanks to the whole Gears team, who pioneered this
1.81 ihickson 2223: technology and whose experience has been a huge influence on this
1.155 ihickson 2224: specification.
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