You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
1745 lines
104 KiB
1745 lines
104 KiB
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
|
<html lang="en-US-x-Hixie" ><head><title>6 Web application APIs — HTML5 </title><style type="text/css">
|
|
pre { margin-left: 2em; white-space: pre-wrap; }
|
|
h2 { margin: 3em 0 1em 0; }
|
|
h3 { margin: 2.5em 0 1em 0; }
|
|
h4 { margin: 2.5em 0 0.75em 0; }
|
|
h5, h6 { margin: 2.5em 0 1em; }
|
|
h1 + h2, h1 + h2 + h2 { margin: 0.75em 0 0.75em; }
|
|
h2 + h3, h3 + h4, h4 + h5, h5 + h6 { margin-top: 0.5em; }
|
|
p { margin: 1em 0; }
|
|
hr:not(.top) { display: block; background: none; border: none; padding: 0; margin: 2em 0; height: auto; }
|
|
dl, dd { margin-top: 0; margin-bottom: 0; }
|
|
dt { margin-top: 0.75em; margin-bottom: 0.25em; clear: left; }
|
|
dt + dt { margin-top: 0; }
|
|
dd dt { margin-top: 0.25em; margin-bottom: 0; }
|
|
dd p { margin-top: 0; }
|
|
dd dl + p { margin-top: 1em; }
|
|
dd table + p { margin-top: 1em; }
|
|
p + * > li, dd li { margin: 1em 0; }
|
|
dt, dfn { font-weight: bold; font-style: normal; }
|
|
dt dfn { font-style: italic; }
|
|
pre, code { font-size: inherit; font-family: monospace; font-variant: normal; }
|
|
pre strong { color: black; font: inherit; font-weight: bold; background: yellow; }
|
|
pre em { font-weight: bolder; font-style: normal; }
|
|
@media screen { code { color: orangered; } code :link, code :visited { color: inherit; } }
|
|
var sub { vertical-align: bottom; font-size: smaller; position: relative; top: 0.1em; }
|
|
table { border-collapse: collapse; border-style: hidden hidden none hidden; }
|
|
table thead, table tbody { border-bottom: solid; }
|
|
table tbody th:first-child { border-left: solid; }
|
|
table tbody th { text-align: left; }
|
|
table td, table th { border-left: solid; border-right: solid; border-bottom: solid thin; vertical-align: top; padding: 0.2em; }
|
|
blockquote { margin: 0 0 0 2em; border: 0; padding: 0; font-style: italic; }
|
|
|
|
.bad, .bad *:not(.XXX) { color: gray; border-color: gray; background: transparent; }
|
|
.matrix, .matrix td { border: none; text-align: right; }
|
|
.matrix { margin-left: 2em; }
|
|
.dice-example { border-collapse: collapse; border-style: hidden solid solid hidden; border-width: thin; margin-left: 3em; }
|
|
.dice-example caption { width: 30em; font-size: smaller; font-style: italic; padding: 0.75em 0; text-align: left; }
|
|
.dice-example td, .dice-example th { border: solid thin; width: 1.35em; height: 1.05em; text-align: center; padding: 0; }
|
|
|
|
.toc dfn, h1 dfn, h2 dfn, h3 dfn, h4 dfn, h5 dfn, h6 dfn { font: inherit; }
|
|
img.extra { float: right; }
|
|
pre.idl { border: solid thin; background: #EEEEEE; color: black; padding: 0.5em 1em; }
|
|
pre.idl :link, pre.idl :visited { color: inherit; background: transparent; }
|
|
pre.css { border: solid thin; background: #FFFFEE; color: black; padding: 0.5em 1em; }
|
|
pre.css:first-line { color: #AAAA50; }
|
|
dl.domintro { color: green; margin: 2em 0 2em 2em; padding: 0.5em 1em; border: none; background: #DDFFDD; }
|
|
hr + dl.domintro, div.impl + dl.domintro { margin-top: 2.5em; margin-bottom: 1.5em; }
|
|
dl.domintro dt, dl.domintro dt * { color: black; text-decoration: none; }
|
|
dl.domintro dd { margin: 0.5em 0 1em 2em; padding: 0; }
|
|
dl.domintro dd p { margin: 0.5em 0; }
|
|
dl.switch { padding-left: 2em; }
|
|
dl.switch > dt { text-indent: -1.5em; }
|
|
dl.switch > dt:before { content: '\21AA'; padding: 0 0.5em 0 0; display: inline-block; width: 1em; text-align: right; line-height: 0.5em; }
|
|
dl.triple { padding: 0 0 0 1em; }
|
|
dl.triple dt, dl.triple dd { margin: 0; display: inline }
|
|
dl.triple dt:after { content: ':'; }
|
|
dl.triple dd:after { content: '\A'; white-space: pre; }
|
|
.diff-old { text-decoration: line-through; color: silver; background: transparent; }
|
|
.diff-chg, .diff-new { text-decoration: underline; color: green; background: transparent; }
|
|
a .diff-new { border-bottom: 1px blue solid; }
|
|
|
|
h2 { page-break-before: always; }
|
|
h1, h2, h3, h4, h5, h6 { page-break-after: avoid; }
|
|
h1 + h2, hr + h2.no-toc { page-break-before: auto; }
|
|
|
|
p > span:not([title=""]):not([class="XXX"]):not([class="impl"]):not([class="note"]),
|
|
li > span:not([title=""]):not([class="XXX"]):not([class="impl"]):not([class="note"]), { border-bottom: solid #9999CC; }
|
|
|
|
div.head { margin: 0 0 1em; padding: 1em 0 0 0; }
|
|
div.head p { margin: 0; }
|
|
div.head h1 { margin: 0; }
|
|
div.head .logo { float: right; margin: 0 1em; }
|
|
div.head .logo img { border: none } /* remove border from top image */
|
|
div.head dl { margin: 1em 0; }
|
|
div.head p.copyright, div.head p.alt { font-size: x-small; font-style: oblique; margin: 0; }
|
|
|
|
body > .toc > li { margin-top: 1em; margin-bottom: 1em; }
|
|
body > .toc.brief > li { margin-top: 0.35em; margin-bottom: 0.35em; }
|
|
body > .toc > li > * { margin-bottom: 0.5em; }
|
|
body > .toc > li > * > li > * { margin-bottom: 0.25em; }
|
|
.toc, .toc li { list-style: none; }
|
|
|
|
.brief { margin-top: 1em; margin-bottom: 1em; line-height: 1.1; }
|
|
.brief li { margin: 0; padding: 0; }
|
|
.brief li p { margin: 0; padding: 0; }
|
|
|
|
.category-list { margin-top: -0.75em; margin-bottom: 1em; line-height: 1.5; }
|
|
.category-list::before { content: '\21D2\A0'; font-size: 1.2em; font-weight: 900; }
|
|
.category-list li { display: inline; }
|
|
.category-list li:not(:last-child)::after { content: ', '; }
|
|
.category-list li > span, .category-list li > a { text-transform: lowercase; }
|
|
.category-list li * { text-transform: none; } /* don't affect <code> nested in <a> */
|
|
|
|
.XXX { color: #E50000; background: white; border: solid red; padding: 0.5em; margin: 1em 0; }
|
|
.XXX > :first-child { margin-top: 0; }
|
|
p .XXX { line-height: 3em; }
|
|
.annotation { border: solid thin black; background: #0C479D; color: white; position: relative; margin: 8px 0 20px 0; }
|
|
.annotation:before { position: absolute; left: 0; top: 0; width: 100%; height: 100%; margin: 6px -6px -6px 6px; background: #333333; z-index: -1; content: ''; }
|
|
.annotation :link, .annotation :visited { color: inherit; }
|
|
.annotation :link:hover, .annotation :visited:hover { background: transparent; }
|
|
.annotation span { border: none ! important; }
|
|
.note { color: green; background: transparent; font-family: sans-serif; }
|
|
.warning { color: red; background: transparent; }
|
|
.note, .warning { font-weight: bolder; font-style: italic; }
|
|
p.note, div.note { padding: 0.5em 2em; }
|
|
span.note { padding: 0 2em; }
|
|
.note p:first-child, .warning p:first-child { margin-top: 0; }
|
|
.note p:last-child, .warning p:last-child { margin-bottom: 0; }
|
|
.warning:before { font-style: normal; }
|
|
p.note:before { content: 'Note: '; }
|
|
p.warning:before { content: '\26A0 Warning! '; }
|
|
|
|
.bookkeeping:before { display: block; content: 'Bookkeeping details'; font-weight: bolder; font-style: italic; }
|
|
.bookkeeping { font-size: 0.8em; margin: 2em 0; }
|
|
.bookkeeping p { margin: 0.5em 2em; display: list-item; list-style: square; }
|
|
.bookkeeping dt { margin: 0.5em 2em 0; }
|
|
.bookkeeping dd { margin: 0 3em 0.5em; }
|
|
|
|
h4 { position: relative; z-index: 3; }
|
|
h4 + .element, h4 + div + .element { margin-top: -2.5em; padding-top: 2em; }
|
|
.element {
|
|
background: #EEEEFF;
|
|
color: black;
|
|
margin: 0 0 1em 0.15em;
|
|
padding: 0 1em 0.25em 0.75em;
|
|
border-left: solid #9999FF 0.25em;
|
|
position: relative;
|
|
z-index: 1;
|
|
}
|
|
.element:before {
|
|
position: absolute;
|
|
z-index: 2;
|
|
top: 0;
|
|
left: -1.15em;
|
|
height: 2em;
|
|
width: 0.9em;
|
|
background: #EEEEFF;
|
|
content: ' ';
|
|
border-style: none none solid solid;
|
|
border-color: #9999FF;
|
|
border-width: 0.25em;
|
|
}
|
|
|
|
.example { display: block; color: #222222; background: #FCFCFC; border-left: double; margin-left: 2em; padding-left: 1em; }
|
|
td > .example:only-child { margin: 0 0 0 0.1em; }
|
|
|
|
ul.domTree, ul.domTree ul { padding: 0 0 0 1em; margin: 0; }
|
|
ul.domTree li { padding: 0; margin: 0; list-style: none; position: relative; }
|
|
ul.domTree li li { list-style: none; }
|
|
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; }
|
|
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; }
|
|
ul.domTree span { font-style: italic; font-family: serif; }
|
|
ul.domTree .t1 code { color: purple; font-weight: bold; }
|
|
ul.domTree .t2 { font-style: normal; font-family: monospace; }
|
|
ul.domTree .t2 .name { color: black; font-weight: bold; }
|
|
ul.domTree .t2 .value { color: blue; font-weight: normal; }
|
|
ul.domTree .t3 code, .domTree .t4 code, .domTree .t5 code { color: gray; }
|
|
ul.domTree .t7 code, .domTree .t8 code { color: green; }
|
|
ul.domTree .t10 code { color: teal; }
|
|
|
|
body.dfnEnabled dfn { cursor: pointer; }
|
|
.dfnPanel {
|
|
display: inline;
|
|
position: absolute;
|
|
z-index: 10;
|
|
height: auto;
|
|
width: auto;
|
|
padding: 0.5em 0.75em;
|
|
font: small sans-serif, Droid Sans Fallback;
|
|
background: #DDDDDD;
|
|
color: black;
|
|
border: outset 0.2em;
|
|
}
|
|
.dfnPanel * { margin: 0; padding: 0; font: inherit; text-indent: 0; }
|
|
.dfnPanel :link, .dfnPanel :visited { color: black; }
|
|
.dfnPanel p { font-weight: bolder; }
|
|
.dfnPanel * + p { margin-top: 0.25em; }
|
|
.dfnPanel li { list-style-position: inside; }
|
|
|
|
#configUI { position: absolute; z-index: 20; top: 10em; right: 1em; width: 11em; font-size: small; }
|
|
#configUI p { margin: 0.5em 0; padding: 0.3em; background: #EEEEEE; color: black; border: inset thin; }
|
|
#configUI p label { display: block; }
|
|
#configUI #updateUI, #configUI .loginUI { text-align: center; }
|
|
#configUI input[type=button] { display: block; margin: auto; }
|
|
|
|
fieldset { margin: 1em; padding: 0.5em 1em; }
|
|
fieldset > legend + * { margin-top: 0; }
|
|
fieldset > :last-child { margin-bottom: 0; }
|
|
fieldset p { margin: 0.5em 0; }
|
|
|
|
.stability {
|
|
position: fixed;
|
|
bottom: 0;
|
|
left: 0; right: 0;
|
|
margin: 0 auto 0 auto !important;
|
|
z-index: 1000;
|
|
width: 50%;
|
|
background: maroon; color: yellow;
|
|
-webkit-border-radius: 1em 1em 0 0;
|
|
-moz-border-radius: 1em 1em 0 0;
|
|
border-radius: 1em 1em 0 0;
|
|
-moz-box-shadow: 0 0 1em #500;
|
|
-webkit-box-shadow: 0 0 1em #500;
|
|
box-shadow: 0 0 1em red;
|
|
padding: 0.5em 1em;
|
|
text-align: center;
|
|
}
|
|
.stability strong {
|
|
display: block;
|
|
}
|
|
.stability input {
|
|
appearance: none; margin: 0; border: 0; padding: 0.25em 0.5em; background: transparent; color: black;
|
|
position: absolute; top: -0.5em; right: 0; font: 1.25em sans-serif; text-align: center;
|
|
}
|
|
.stability input:hover {
|
|
color: white;
|
|
text-shadow: 0 0 2px black;
|
|
}
|
|
.stability input:active {
|
|
padding: 0.3em 0.45em 0.2em 0.55em;
|
|
}
|
|
.stability :link, .stability :visited,
|
|
.stability :link:hover, .stability :visited:hover {
|
|
background: transparent;
|
|
color: white;
|
|
}
|
|
|
|
</style><link href="data:text/css,.impl%20%7B%20display:%20none;%20%7D%0Ahtml%20%7B%20border:%20solid%20yellow;%20%7D%20.domintro:before%20%7B%20display:%20none;%20%7D" id="author" rel="alternate stylesheet" title="Author documentation only"><link href="data:text/css,.impl%20%7B%20background:%20%23FFEEEE;%20%7D%20.domintro:before%20%7B%20background:%20%23FFEEEE;%20%7D" id="highlight" rel="alternate stylesheet" title="Highlight implementation
|
|
requirements"><link href="http://www.w3.org/StyleSheets/TR/W3C-WD" rel="stylesheet" type="text/css"><style type="text/css">
|
|
|
|
.applies thead th > * { display: block; }
|
|
.applies thead code { display: block; }
|
|
.applies tbody th { whitespace: nowrap; }
|
|
.applies td { text-align: center; }
|
|
.applies .yes { background: yellow; }
|
|
|
|
.matrix, .matrix td { border: hidden; text-align: right; }
|
|
.matrix { margin-left: 2em; }
|
|
|
|
.dice-example { border-collapse: collapse; border-style: hidden solid solid hidden; border-width: thin; margin-left: 3em; }
|
|
.dice-example caption { width: 30em; font-size: smaller; font-style: italic; padding: 0.75em 0; text-align: left; }
|
|
.dice-example td, .dice-example th { border: solid thin; width: 1.35em; height: 1.05em; text-align: center; padding: 0; }
|
|
|
|
td.eg { border-width: thin; text-align: center; }
|
|
|
|
#table-example-1 { border: solid thin; border-collapse: collapse; margin-left: 3em; }
|
|
#table-example-1 * { font-family: "Essays1743", serif; line-height: 1.01em; }
|
|
#table-example-1 caption { padding-bottom: 0.5em; }
|
|
#table-example-1 thead, #table-example-1 tbody { border: none; }
|
|
#table-example-1 th, #table-example-1 td { border: solid thin; }
|
|
#table-example-1 th { font-weight: normal; }
|
|
#table-example-1 td { border-style: none solid; vertical-align: top; }
|
|
#table-example-1 th { padding: 0.5em; vertical-align: middle; text-align: center; }
|
|
#table-example-1 tbody tr:first-child td { padding-top: 0.5em; }
|
|
#table-example-1 tbody tr:last-child td { padding-bottom: 1.5em; }
|
|
#table-example-1 tbody td:first-child { padding-left: 2.5em; padding-right: 0; width: 9em; }
|
|
#table-example-1 tbody td:first-child::after { content: leader(". "); }
|
|
#table-example-1 tbody td { padding-left: 2em; padding-right: 2em; }
|
|
#table-example-1 tbody td:first-child + td { width: 10em; }
|
|
#table-example-1 tbody td:first-child + td ~ td { width: 2.5em; }
|
|
#table-example-1 tbody td:first-child + td + td + td ~ td { width: 1.25em; }
|
|
|
|
.apple-table-examples { border: none; border-collapse: separate; border-spacing: 1.5em 0em; width: 40em; margin-left: 3em; }
|
|
.apple-table-examples * { font-family: "Times", serif; }
|
|
.apple-table-examples td, .apple-table-examples th { border: none; white-space: nowrap; padding-top: 0; padding-bottom: 0; }
|
|
.apple-table-examples tbody th:first-child { border-left: none; width: 100%; }
|
|
.apple-table-examples thead th:first-child ~ th { font-size: smaller; font-weight: bolder; border-bottom: solid 2px; text-align: center; }
|
|
.apple-table-examples tbody th::after, .apple-table-examples tfoot th::after { content: leader(". ") }
|
|
.apple-table-examples tbody th, .apple-table-examples tfoot th { font: inherit; text-align: left; }
|
|
.apple-table-examples td { text-align: right; vertical-align: top; }
|
|
.apple-table-examples.e1 tbody tr:last-child td { border-bottom: solid 1px; }
|
|
.apple-table-examples.e1 tbody + tbody tr:last-child td { border-bottom: double 3px; }
|
|
.apple-table-examples.e2 th[scope=row] { padding-left: 1em; }
|
|
.apple-table-examples sup { line-height: 0; }
|
|
|
|
.details-example img { vertical-align: top; }
|
|
|
|
#base64-table {
|
|
white-space: nowrap;
|
|
font-size: 0.6em;
|
|
column-width: 6em;
|
|
column-count: 5;
|
|
column-gap: 1em;
|
|
-moz-column-width: 6em;
|
|
-moz-column-count: 5;
|
|
-moz-column-gap: 1em;
|
|
-webkit-column-width: 6em;
|
|
-webkit-column-count: 5;
|
|
-webkit-column-gap: 1em;
|
|
}
|
|
#base64-table thead { display: none; }
|
|
#base64-table * { border: none; }
|
|
#base64-table tbody td:first-child:after { content: ':'; }
|
|
#base64-table tbody td:last-child { text-align: right; }
|
|
|
|
#named-character-references-table {
|
|
white-space: nowrap;
|
|
font-size: 0.6em;
|
|
column-width: 30em;
|
|
column-gap: 1em;
|
|
-moz-column-width: 30em;
|
|
-moz-column-gap: 1em;
|
|
-webkit-column-width: 30em;
|
|
-webkit-column-gap: 1em;
|
|
}
|
|
#named-character-references-table > table > tbody > tr > td:first-child + td,
|
|
#named-character-references-table > table > tbody > tr > td:last-child { text-align: center; }
|
|
#named-character-references-table > table > tbody > tr > td:last-child:hover > span { position: absolute; top: auto; left: auto; margin-left: 0.5em; line-height: 1.2; font-size: 5em; border: outset; padding: 0.25em 0.5em; background: white; width: 1.25em; height: auto; text-align: center; }
|
|
#named-character-references-table > table > tbody > tr#entity-CounterClockwiseContourIntegral > td:first-child { font-size: 0.5em; }
|
|
|
|
.glyph.control { color: red; }
|
|
|
|
@font-face {
|
|
font-family: 'Essays1743';
|
|
src: url('http://www.whatwg.org/specs/web-apps/current-work/fonts/Essays1743.ttf');
|
|
}
|
|
@font-face {
|
|
font-family: 'Essays1743';
|
|
font-weight: bold;
|
|
src: url('http://www.whatwg.org/specs/web-apps/current-work/fonts/Essays1743-Bold.ttf');
|
|
}
|
|
@font-face {
|
|
font-family: 'Essays1743';
|
|
font-style: italic;
|
|
src: url('http://www.whatwg.org/specs/web-apps/current-work/fonts/Essays1743-Italic.ttf');
|
|
}
|
|
@font-face {
|
|
font-family: 'Essays1743';
|
|
font-style: italic;
|
|
font-weight: bold;
|
|
src: url('http://www.whatwg.org/specs/web-apps/current-work/fonts/Essays1743-BoldItalic.ttf');
|
|
}
|
|
|
|
</style><style type="text/css">
|
|
.domintro:before { display: table; margin: -1em -0.5em -0.5em auto; width: auto; content: 'This box is non-normative. Implementation requirements are given below this box.'; color: black; font-style: italic; border: solid 2px; background: white; padding: 0 0.25em; }
|
|
</style><script type="text/javascript">
|
|
function getCookie(name) {
|
|
var params = location.search.substr(1).split("&");
|
|
for (var index = 0; index < params.length; index++) {
|
|
if (params[index] == name)
|
|
return "1";
|
|
var data = params[index].split("=");
|
|
if (data[0] == name)
|
|
return unescape(data[1]);
|
|
}
|
|
var cookies = document.cookie.split("; ");
|
|
for (var index = 0; index < cookies.length; index++) {
|
|
var data = cookies[index].split("=");
|
|
if (data[0] == name)
|
|
return unescape(data[1]);
|
|
}
|
|
return null;
|
|
}
|
|
</script>
|
|
<script src="link-fixup.js" type="text/javascript"></script>
|
|
<link href="style.css" rel="stylesheet"><link href="offline.html" title="5.6 Offline Web applications" rel="prev">
|
|
<link href="spec.html#contents" title="Table of contents" rel="index">
|
|
<link href="timers.html" title="6.3 Timers" rel="next">
|
|
</head><body><div class="head" id="head">
|
|
<div id="multipage-common">
|
|
<p class="stability" id="wip"><strong>This is a work in
|
|
progress!</strong> For the latest updates from the HTML WG, possibly
|
|
including important bug fixes, please look at the <a href="http://dev.w3.org/html5/spec/Overview.html">editor's draft</a> instead.
|
|
There may also be a more
|
|
<a href="http://www.w3.org/TR/html5">up-to-date Working Draft</a>
|
|
with changes based on resolution of Last Call issues.
|
|
<input onclick="closeWarning(this.parentNode)" type="button" value="╳⃝"></p>
|
|
<script type="text/javascript">
|
|
function closeWarning(element) {
|
|
element.parentNode.removeChild(element);
|
|
var date = new Date();
|
|
date.setDate(date.getDate()+4);
|
|
document.cookie = 'hide-obsolescence-warning=1; expires=' + date.toGMTString();
|
|
}
|
|
if (getCookie('hide-obsolescence-warning') == '1')
|
|
setTimeout(function () { document.getElementById('wip').parentNode.removeChild(document.getElementById('wip')); }, 2000);
|
|
</script></div>
|
|
|
|
<p><a href="http://www.w3.org/"><img alt="W3C" height="48" src="http://www.w3.org/Icons/w3c_home" width="72"></a></p>
|
|
|
|
<h1>HTML5</h1>
|
|
</div><div>
|
|
<a href="offline.html" class="prev">5.6 Offline Web applications</a> –
|
|
<a href="spec.html#contents">Table of contents</a> –
|
|
<a href="timers.html" class="next">6.3 Timers</a>
|
|
<ol class="toc"><li><a href="webappapis.html#webappapis"><span class="secno">6 </span>Web application APIs</a>
|
|
<ol><li><a href="webappapis.html#scripting"><span class="secno">6.1 </span>Scripting</a>
|
|
<ol><li><a href="webappapis.html#introduction-5"><span class="secno">6.1.1 </span>Introduction</a></li><li><a href="webappapis.html#enabling-and-disabling-scripting"><span class="secno">6.1.2 </span>Enabling and disabling scripting</a></li><li><a href="webappapis.html#processing-model-1"><span class="secno">6.1.3 </span>Processing model</a>
|
|
<ol><li><a href="webappapis.html#definitions-0"><span class="secno">6.1.3.1 </span>Definitions</a></li><li><a href="webappapis.html#calling-scripts"><span class="secno">6.1.3.2 </span>Calling scripts</a></li><li><a href="webappapis.html#creating-scripts"><span class="secno">6.1.3.3 </span>Creating scripts</a></li><li><a href="webappapis.html#killing-scripts"><span class="secno">6.1.3.4 </span>Killing scripts</a></li><li><a href="webappapis.html#runtime-script-errors"><span class="secno">6.1.3.5 </span>Runtime script errors</a></li></ol></li><li><a href="webappapis.html#event-loops"><span class="secno">6.1.4 </span>Event loops</a>
|
|
<ol><li><a href="webappapis.html#definitions-1"><span class="secno">6.1.4.1 </span>Definitions</a></li><li><a href="webappapis.html#processing-model-2"><span class="secno">6.1.4.2 </span>Processing model</a></li><li><a href="webappapis.html#generic-task-sources"><span class="secno">6.1.4.3 </span>Generic task sources</a></li></ol></li><li><a href="webappapis.html#javascript-protocol"><span class="secno">6.1.5 </span>The <code title="">javascript:</code> URL scheme</a></li><li><a href="webappapis.html#events"><span class="secno">6.1.6 </span>Events</a>
|
|
<ol><li><a href="webappapis.html#event-handler-attributes"><span class="secno">6.1.6.1 </span>Event handlers</a></li><li><a href="webappapis.html#event-handlers-on-elements-document-objects-and-window-objects"><span class="secno">6.1.6.2 </span>Event handlers on elements, <code>Document</code> objects, and <code>Window</code> objects</a></li><li><a href="webappapis.html#event-firing"><span class="secno">6.1.6.3 </span>Event firing</a></li><li><a href="webappapis.html#events-and-the-window-object"><span class="secno">6.1.6.4 </span>Events and the <code>Window</code> object</a></li></ol></li></ol></li><li><a href="webappapis.html#atob"><span class="secno">6.2 </span>Base64 utility methods</a></li></ol></li></ol></div>
|
|
|
|
<h2 id="webappapis"><span class="secno">6 </span>Web application APIs</h2><h3 id="scripting"><span class="secno">6.1 </span>Scripting</h3><h4 id="introduction-5"><span class="secno">6.1.1 </span>Introduction</h4><p>Various mechanisms can cause author-provided executable code to
|
|
run in the context of a document. These mechanisms include, but are
|
|
probably not limited to:</p><ul><li>Processing of <code><a href="scripting-1.html#the-script-element">script</a></code> elements.</li>
|
|
|
|
<li>Processing of inline <code title="javascript
|
|
protocol"><a href="#javascript-protocol">javascript:</a></code> URLs (e.g. the <code title="attr-img-src"><a href="embedded-content-1.html#attr-img-src">src</a></code> attribute of <code><a href="embedded-content-1.html#the-img-element">img</a></code>
|
|
elements, or an <code title="">@import</code> rule in a CSS
|
|
<code><a href="semantics.html#the-style-element">style</a></code> element block).</li>
|
|
|
|
<li>Event handlers, whether registered through the DOM using <code title="">addEventListener()</code>, by explicit <a href="#event-handler-content-attributes">event handler
|
|
content attributes</a>, by <a href="#event-handler-idl-attributes">event handler IDL
|
|
attributes</a>, or otherwise.</li>
|
|
|
|
<li>Processing of technologies like XBL or SVG that have their own
|
|
scripting features.</li>
|
|
|
|
</ul><div class="impl">
|
|
|
|
<h4 id="enabling-and-disabling-scripting"><span class="secno">6.1.2 </span>Enabling and disabling scripting</h4>
|
|
|
|
<p><dfn id="concept-bc-script" title="concept-bc-script">Scripting is enabled</dfn> in a
|
|
<em><a href="browsers.html#browsing-context">browsing context</a></em> when all of the
|
|
following conditions are true:</p>
|
|
|
|
<ul><li>The user agent supports scripting.</li>
|
|
|
|
<li>The user has not disabled scripting for this <a href="browsers.html#browsing-context">browsing
|
|
context</a> at this time. (User agents may provide users with
|
|
the option to disable scripting globally, or in a finer-grained
|
|
manner, e.g. on a per-origin basis.)</li>
|
|
|
|
<li id="sandboxScriptBlocked">The <a href="browsers.html#browsing-context">browsing context</a> did
|
|
not have the <a href="the-iframe-element.html#sandboxed-scripts-browsing-context-flag">sandboxed scripts browsing context flag</a>
|
|
set when the <a href="browsers.html#browsing-context">browsing context</a>'s <a href="browsers.html#active-document">active
|
|
document</a> was created.</li>
|
|
|
|
</ul><p><dfn id="concept-bc-noscript" title="concept-bc-noscript">Scripting is disabled</dfn> in a
|
|
<a href="browsers.html#browsing-context">browsing context</a> when any of the above conditions are
|
|
false (i.e. when scripting is not <a href="#concept-bc-script" title="concept-bc-script">enabled</a>).</p>
|
|
|
|
<hr><p><dfn id="concept-n-script" title="concept-n-script">Scripting is enabled</dfn> for a
|
|
<em>node</em> if the <code><a href="infrastructure.html#document">Document</a></code> object of the node (the
|
|
node itself, if it is itself a <code><a href="infrastructure.html#document">Document</a></code> object) has an
|
|
associated <a href="browsers.html#browsing-context">browsing context</a>, and <a href="#concept-bc-script" title="concept-bc-script">scripting is enabled</a> in that
|
|
<a href="browsers.html#browsing-context">browsing context</a>.</p>
|
|
|
|
<p><dfn id="concept-n-noscript" title="concept-n-noscript">Scripting is disabled</dfn> for a
|
|
node if there is no such <a href="browsers.html#browsing-context">browsing context</a>, or if <a href="#concept-bc-noscript" title="concept-bc-noscript">scripting is disabled</a> in that
|
|
<a href="browsers.html#browsing-context">browsing context</a>.</p>
|
|
|
|
</div><div class="impl">
|
|
|
|
|
|
<h4 id="processing-model-1"><span class="secno">6.1.3 </span>Processing model</h4>
|
|
|
|
<h5 id="definitions-0"><span class="secno">6.1.3.1 </span>Definitions</h5>
|
|
|
|
<p>A <dfn id="concept-script" title="concept-script">script</dfn> has:</p>
|
|
|
|
<dl><dt>A <dfn id="script-execution-environment">script execution environment</dfn></dt>
|
|
|
|
<dd>
|
|
|
|
<p>The characteristics of the script execution environment depend
|
|
on the language, and are not defined by this specification.</p>
|
|
|
|
<p class="example">In JavaScript, the script execution environment
|
|
consists of the interpreter, the stack of <i>execution
|
|
contexts</i>, the <i>global code</i> and <i>function code</i> and
|
|
the Function objects resulting, and so forth.</p>
|
|
|
|
</dd>
|
|
|
|
<dt>A <dfn id="list-of-code-entry-points">list of code entry-points</dfn></dt>
|
|
|
|
<dd>
|
|
|
|
<p>Each code entry-point represents a block of executable code
|
|
that the script exposes to other scripts and to the user
|
|
agent.</p>
|
|
|
|
<p class="example">Each Function object in a JavaScript
|
|
<a href="#script-execution-environment">script execution environment</a> has a corresponding code
|
|
entry-point, for instance.</p>
|
|
|
|
<p>The main program code of the script, if any, is the
|
|
<dfn id="initial-code-entry-point"><i>initial code entry-point</i></dfn>. Typically, the code
|
|
corresponding to this entry-point is executed immediately after
|
|
the script is parsed.</p>
|
|
|
|
<p class="example">In JavaScript, this corresponds to the
|
|
execution context of the global code.</p>
|
|
|
|
</dd>
|
|
|
|
<dt>A relationship with the <dfn id="script-s-global-object">script's global object</dfn></dt>
|
|
|
|
<dd>
|
|
|
|
<p>An object that provides the APIs that the code can use.</p>
|
|
|
|
<p class="example">This is typically a <code><a href="browsers.html#window">Window</a></code>
|
|
object. In JavaScript, this corresponds to the <i>global
|
|
object</i>.</p>
|
|
|
|
<p class="note">When a <a href="#script-s-global-object">script's global object</a> is an
|
|
empty object, it can't do anything that interacts with the
|
|
environment.</p>
|
|
|
|
<p>If the <a href="#script-s-global-object">script's global object</a> is a
|
|
<code><a href="browsers.html#window">Window</a></code> object, then in JavaScript, the ThisBinding of
|
|
the global execution context for this script must be the
|
|
<code><a href="browsers.html#window">Window</a></code> object's <code><a href="browsers.html#windowproxy">WindowProxy</a></code> object,
|
|
rather than the global object. <a href="references.html#refsECMA262">[ECMA262]</a></p>
|
|
|
|
<p class="note">This is a <a href="introduction.html#willful-violation">willful violation</a> of the
|
|
JavaScript specification current at the time of writing
|
|
(ECMAScript edition 5, as defined in section 10.4.1.1 Initial
|
|
Global Execution Context, step 3). The JavaScript specification
|
|
requires that the <code title="">this</code> keyword in the global
|
|
scope return the global object, but this is not compatible with
|
|
the security design prevalent in implementations as specified
|
|
herein. <a href="references.html#refsECMA262">[ECMA262]</a></p>
|
|
|
|
</dd>
|
|
|
|
<dt>A relationship with the <dfn id="script-s-browsing-context">script's browsing context</dfn></dt>
|
|
|
|
<dd>
|
|
|
|
<p>A <a href="browsers.html#browsing-context">browsing context</a> that is assigned responsibility
|
|
for actions taken by the script.</p>
|
|
|
|
<p class="example">When a script creates and <a href="history.html#navigate" title="navigate">navigates</a> a new <a href="browsers.html#top-level-browsing-context">top-level browsing
|
|
context</a>, the <code title="dom-opener"><a href="browsers.html#dom-opener">opener</a></code>
|
|
attribute of the new <a href="browsers.html#browsing-context">browsing context</a>'s
|
|
<code><a href="browsers.html#window">Window</a></code> object will be set to the <a href="#script-s-browsing-context">script's
|
|
browsing context</a>'s <code><a href="browsers.html#windowproxy">WindowProxy</a></code> object.</p>
|
|
|
|
</dd>
|
|
|
|
<dt>A relationship with the <dfn id="script-s-document">script's document</dfn></dt>
|
|
|
|
<dd>
|
|
|
|
<p>A <code><a href="infrastructure.html#document">Document</a></code> that is assigned responsibility for
|
|
actions taken by the script.</p>
|
|
|
|
<p class="example">When a script <a href="fetching-resources.html#fetch" title="fetch">fetches</a> a resource, the <a href="dom.html#the-document-s-current-address" title="the
|
|
document's current address">current address</a> of the
|
|
<a href="#script-s-document">script's document</a> will be used to set the <code title="http-referer">Referer</code> (sic) header.</p>
|
|
|
|
</dd>
|
|
|
|
<dt>A <dfn id="script-s-url-character-encoding" title="script's URL character encoding">URL character encoding</dfn></dt>
|
|
|
|
<dd>
|
|
|
|
<p>A character encoding, set when the script is created, used to
|
|
encode URLs. <span id="sce-not-copy" title="">If the character
|
|
encoding is set from another source, e.g. a <a href="dom.html#document-s-character-encoding">document's
|
|
character encoding</a>, then the <a href="#script-s-url-character-encoding">script's URL character
|
|
encoding</a> must follow the source, so that if the source's
|
|
changes, so does the script's.</span></p>
|
|
|
|
</dd>
|
|
|
|
<dt>A <dfn id="script-s-base-url" title="script's base URL">base URL</dfn></dt>
|
|
|
|
<dd>
|
|
|
|
<p>A <a href="urls.html#url">URL</a>, set when the script is created, used to
|
|
resolve relative URLs. <span id="sbu-not-copy" title="">If the
|
|
base URL is set from another source, e.g. a <a href="urls.html#document-base-url">document base
|
|
URL</a>, then the <a href="#script-s-base-url">script's base URL</a> must follow
|
|
the source, so that if the source's changes, so does the
|
|
script's.</span></p>
|
|
|
|
</dd>
|
|
|
|
</dl></div><div class="impl">
|
|
|
|
<h5 id="calling-scripts"><span class="secno">6.1.3.2 </span>Calling scripts</h5>
|
|
|
|
<p>When a user agent is to <dfn id="jump-to-a-code-entry-point">jump to a code entry-point</dfn> for
|
|
a <a href="#concept-script" title="concept-script">script</a>, for example to invoke
|
|
an event listener defined in that <a href="#concept-script" title="concept-script">script</a>, the user agent must run the
|
|
following steps:</p>
|
|
|
|
<ol><li><p>If the <a href="#script-s-global-object">script's global object</a> is a
|
|
<code><a href="browsers.html#window">Window</a></code> object whose <code><a href="infrastructure.html#document">Document</a></code> object is
|
|
not <a href="browsers.html#fully-active">fully active</a>, then abort these steps without doing
|
|
anything. The callback is not fired.</p>
|
|
|
|
</li><li><p>Set the <a href="browsers.html#entry-script">entry script</a> to be the <a href="#concept-script" title="concept-script">script</a> being invoked.</p></li>
|
|
|
|
<li><p>Make the <a href="#script-execution-environment" title="script execution environment">script
|
|
execution environment</a> for the <a href="#concept-script" title="concept-script">script</a> execute the code for the given
|
|
code entry-point.</p></li>
|
|
|
|
<li><p>Set the <a href="browsers.html#entry-script">entry script</a> back to whatever it was
|
|
when this algorithm started.</p></li>
|
|
|
|
</ol><p>This algorithm is not invoked by one script calling another.</p>
|
|
|
|
</div><div class="impl">
|
|
|
|
<h5 id="creating-scripts"><span class="secno">6.1.3.3 </span>Creating scripts</h5>
|
|
|
|
<p>When the specification says that a <a href="#concept-script" title="concept-script">script</a> is to be <dfn id="create-a-script" title="create a
|
|
script">created</dfn>, given some script source, its scripting
|
|
language, a global object, a browsing context, a URL character
|
|
encoding, and a base URL, the user agent must run the following
|
|
steps:</p>
|
|
|
|
<ol><li><p>If <a href="#concept-bc-noscript" title="concept-bc-noscript">scripting is
|
|
disabled</a> for <a href="browsers.html#browsing-context">browsing context</a> passed to this
|
|
algorithm, then abort these steps, as if the script did nothing but
|
|
return void.</p>
|
|
|
|
</li><li><p>Set up a <a href="#script-execution-environment">script execution environment</a> as
|
|
appropriate for the scripting language.</p></li>
|
|
|
|
<li><p>Parse/compile/initialize the source of the script using the
|
|
<a href="#script-execution-environment">script execution environment</a>, as appropriate for the
|
|
scripting language, and thus obtain the <a href="#list-of-code-entry-points">list of code
|
|
entry-points</a> for the script. If the semantics of the
|
|
scripting language and the given source code are such that there is
|
|
executable code to be immediately run, then the <i><a href="#initial-code-entry-point">initial code
|
|
entry-point</a></i> is the entry-point for that code.</p></li>
|
|
|
|
<li><p>Set up the <a href="#script-s-global-object">script's global object</a>, the
|
|
<a href="#script-s-browsing-context">script's browsing context</a>, the <a href="#script-s-document">script's
|
|
document</a>, the <a href="#script-s-url-character-encoding">script's URL character encoding</a>,
|
|
and the <a href="#script-s-base-url">script's base URL</a> from the settings passed to
|
|
this algorithm.</p></li>
|
|
|
|
<li>
|
|
|
|
<p>If all the steps above succeeded (in particular, if the script
|
|
was compiled successfully), <a href="#jump-to-a-code-entry-point" title="jump to a code
|
|
entry-point">Jump</a> to the <a href="#concept-script" title="concept-script">script</a>'s <i><a href="#initial-code-entry-point">initial code
|
|
entry-point</a></i>.</p>
|
|
|
|
<p>Otherwise, <a href="#report-the-error">report the error</a> using the <code title="handler-window-onerror"><a href="#handler-window-onerror">onerror</a></code> <a href="#event-handlers" title="event
|
|
handlers">event handler</a> of the <a href="#script-s-global-object">script's global
|
|
object</a>. If the error is still <i title="concept-error-nothandled"><a href="#concept-error-nothandled">not handled</a></i> after this, then
|
|
the error may be reported to the user.</p>
|
|
|
|
</li>
|
|
|
|
</ol><hr><p>When the user agent is to <dfn id="create-an-impotent-script">create an impotent script</dfn>,
|
|
given some script source, its scripting language, and a browsing
|
|
context, the user agent must <a href="#create-a-script">create a script</a>, using the
|
|
given script source and scripting language, using a new empty object
|
|
as the global object, and using the given browsing context as the
|
|
browsing context. The URL character encoding and base URL for the
|
|
resulting <a href="#concept-script" title="concept-script">script</a> are not
|
|
important as no APIs are exposed to the script.</p>
|
|
|
|
<hr><p>When the specification says that a <a href="#concept-script" title="concept-script">script</a> is to be <dfn id="create-a-script-from-a-node" title="create a
|
|
script from a node">created from a node</dfn> <var title="">node</var>, given some script source and its scripting
|
|
language, the user agent must <a href="#create-a-script">create a script</a>, using
|
|
the given script source and scripting language, and using <a href="#the-script-settings-determined-from-the-node">the
|
|
script settings determined from the node</a> <var title="">node</var>.</p>
|
|
|
|
<p><dfn id="the-script-settings-determined-from-the-node">The script settings determined from the node</dfn> <var title="">node</var> are computed as follows:</p>
|
|
|
|
<ol><li><p>Let <var title="">document</var> be the
|
|
<code><a href="infrastructure.html#document">Document</a></code> of <var title="">node</var> (or <var title="">node</var> itself if it is a
|
|
<code><a href="infrastructure.html#document">Document</a></code>).</p></li>
|
|
|
|
<li><p>The browsing context is the <a href="browsers.html#browsing-context">browsing context</a> of
|
|
<var title="">document</var>.</p>
|
|
|
|
</li><li><p>The global object is the <code><a href="browsers.html#window">Window</a></code> object of
|
|
<var title="">document</var>.</p></li>
|
|
|
|
<li><p>The URL character encoding is the <a href="dom.html#document-s-character-encoding" title="document's
|
|
character encoding">character encoding</a> of <var title="">document</var>. (<a href="#sce-not-copy">This is a
|
|
reference, not a copy</a>.)</p></li>
|
|
|
|
<li><p>The base URL is the <a href="urls.html#document-base-url" title="document base URL">base
|
|
URL</a> of <var title="">document</var>. (<a href="#sbu-not-copy">This is a reference, not a copy</a>.)</p></li>
|
|
|
|
</ol></div><div class="impl">
|
|
|
|
<h5 id="killing-scripts"><span class="secno">6.1.3.4 </span>Killing scripts</h5>
|
|
|
|
<p>User agents may impose resource limitations on scripts, for
|
|
example CPU quotas, memory limits, total execution time limits, or
|
|
bandwidth limitations. When a script exceeds a limit, the user agent
|
|
may either throw a <code><a href="common-dom-interfaces.html#quota_exceeded_err">QUOTA_EXCEEDED_ERR</a></code> exception, abort
|
|
the script without an exception, prompt the user, or throttle script
|
|
execution.</p>
|
|
|
|
<div class="example">
|
|
|
|
<p>For example, the following script never terminates. A user agent
|
|
could, after waiting for a few seconds, prompt the user to either
|
|
terminate the script or let it continue.</p>
|
|
|
|
<pre><script>
|
|
while (true) { /* loop */ }
|
|
</script></pre>
|
|
|
|
</div>
|
|
|
|
<p>User agents are encouraged to allow users to disable scripting
|
|
whenever the user is prompted either by a script (e.g. using the
|
|
<code title="dom-alert"><a href="timers.html#dom-alert">window.alert()</a></code> API) or because of a
|
|
script's actions (e.g. because it has exceeded a time limit).</p>
|
|
|
|
<p>If scripting is disabled while a script is executing, the script
|
|
should be terminated immediately.</p>
|
|
|
|
</div><div class="impl">
|
|
|
|
<h5 id="runtime-script-errors"><span class="secno">6.1.3.5 </span>Runtime script errors</h5>
|
|
|
|
<p>Whenever an uncaught runtime script error occurs in one of the
|
|
scripts associated with a <code><a href="infrastructure.html#document">Document</a></code>, the user agent must
|
|
<a href="#report-the-error">report the error</a> using the <code title="handler-window-onerror"><a href="#handler-window-onerror">onerror</a></code> <a href="#event-handlers" title="event
|
|
handlers">event handler</a> of the <a href="#script-s-global-object">script's global
|
|
object</a>. If the error is still <i title="concept-error-nothandled"><a href="#concept-error-nothandled">not handled</a></i> after this, then
|
|
the error may be reported to the user.</p>
|
|
|
|
<hr><p>When the user agent is required to <dfn id="report-the-error" title="report the
|
|
error">report an error</dfn> <var title="">error</var> using the
|
|
<a href="#event-handlers" title="event handlers">event handler</a> <var title="">onerror</var>, it must run these steps, after which the
|
|
error is either <dfn id="concept-error-handled" title="concept-error-handled"><i>handled</i></dfn> or <dfn id="concept-error-nothandled" title="concept-error-nothandled"><i>not handled</i></dfn>:</p>
|
|
|
|
<dl class="switch"><dt>If the value of <var title="">onerror</var> is a
|
|
<code><a href="#function">Function</a></code></dt>
|
|
|
|
<dd>
|
|
|
|
<p>The function must be invoked with three arguments. The three
|
|
arguments passed to the function are all <code>DOMString</code>s;
|
|
the first must give the message that the UA is considering
|
|
reporting, the second must give the <a href="urls.html#absolute-url">absolute URL</a> of
|
|
the resource in which the error occurred, and the third must give
|
|
the line number in that resource on which the error occurred.</p>
|
|
|
|
<p>If the function returns false, then the error is <i title="concept-error-handled"><a href="#concept-error-handled">handled</a></i>. Otherwise, the error is
|
|
<i title="concept-error-nothandled"><a href="#concept-error-nothandled">not handled</a></i>.</p>
|
|
|
|
<p>Any uncaught exceptions thrown or errors caused by this
|
|
function may be reported to the user immediately after the error
|
|
that the function was called for; the <a href="#report-the-error" title="report the
|
|
error">report an error</a> algorithm must not be used to handle
|
|
exceptions thrown or errors caused by this function.</p>
|
|
|
|
</dd>
|
|
|
|
<dt>Otherwise</dt>
|
|
|
|
<dd>
|
|
|
|
<p>The error is <i title="concept-error-nothandled"><a href="#concept-error-nothandled">not handled</a></i>.</p>
|
|
|
|
</dd>
|
|
|
|
</dl></div><div class="impl">
|
|
|
|
<h4 id="event-loops"><span class="secno">6.1.4 </span>Event loops</h4>
|
|
|
|
<h5 id="definitions-1"><span class="secno">6.1.4.1 </span>Definitions</h5>
|
|
|
|
<p>To coordinate events, user interaction, scripts, rendering,
|
|
networking, and so forth, user agents must use <dfn id="event-loop" title="event
|
|
loop">event loops</dfn> as described in this section.</p>
|
|
|
|
<p>There must be at least one <a href="#event-loop">event loop</a> per user
|
|
agent, and at most one <a href="#event-loop">event loop</a> per <a href="browsers.html#unit-of-related-similar-origin-browsing-contexts">unit of
|
|
related similar-origin browsing contexts</a>.</p>
|
|
|
|
<p class="note">When there is more than one <a href="#event-loop">event loop</a>
|
|
for a <a href="browsers.html#unit-of-related-browsing-contexts">unit of related browsing contexts</a>, complications
|
|
arise when a <a href="browsers.html#browsing-context">browsing context</a> in that group is <a href="history.html#navigate" title="navigate">navigated</a> such that it switches from one
|
|
<a href="browsers.html#unit-of-related-similar-origin-browsing-contexts">unit of related similar-origin browsing contexts</a> to
|
|
another. This specification does not currently describe how to
|
|
handle these complications.</p>
|
|
|
|
<p>An <a href="#event-loop">event loop</a> always has at least one <a href="browsers.html#browsing-context">browsing
|
|
context</a>. If an <a href="#event-loop">event loop</a>'s <a href="browsers.html#browsing-context" title="browsing context">browsing contexts</a> all go away, then
|
|
the <a href="#event-loop">event loop</a> goes away as well. A <a href="browsers.html#browsing-context">browsing
|
|
context</a> always has an <a href="#event-loop">event loop</a> coordinating
|
|
its activities.</p>
|
|
|
|
|
|
<p class="note">Other specifications can define new kinds of event
|
|
loops that aren't associated with browsing contexts; in particular,
|
|
the Web Workers specification does so.</p>
|
|
|
|
|
|
<p>An <a href="#event-loop">event loop</a> has one or more <dfn id="task-queue" title="task
|
|
queue">task queues</dfn>. A <a href="#task-queue">task queue</a> is an ordered
|
|
list of <dfn id="concept-task" title="concept-task">tasks</dfn>, which can be:</p>
|
|
|
|
<dl><dt>Events</dt>
|
|
|
|
<dd>
|
|
|
|
<p>Asynchronously dispatching an <code><a href="infrastructure.html#event">Event</a></code> object at a
|
|
particular <code><a href="infrastructure.html#eventtarget">EventTarget</a></code> object is a task.</p>
|
|
|
|
<p class="note">Not all events are dispatched using the <a href="#task-queue">task
|
|
queue</a>, many are dispatched synchronously during other
|
|
tasks.</p>
|
|
|
|
</dd>
|
|
|
|
|
|
<dt>Parsing</dt>
|
|
|
|
<dd><p>The <a href="parsing.html#html-parser">HTML parser</a> tokenizing one or more bytes,
|
|
and then processing any resulting tokens, is typically a
|
|
task.</p></dd>
|
|
|
|
|
|
<dt>Callbacks</dt>
|
|
|
|
<dd><p>Calling a callback asynchronously is a task.</p></dd>
|
|
|
|
|
|
<dt>Using a resource</dt>
|
|
|
|
<dd><p>When an algorithm <a href="fetching-resources.html#fetch" title="fetch">fetches</a> a
|
|
resource, if the fetching occurs asynchronously then the processing
|
|
of the resource once some or all of the resource is available is a
|
|
task.</p></dd>
|
|
|
|
|
|
<dt>Reacting to DOM manipulation</dt>
|
|
|
|
<dd><p>Some elements have tasks that trigger in response to DOM
|
|
manipulation, e.g. when that element is <a href="infrastructure.html#insert-an-element-into-a-document" title="insert an
|
|
element into a document">inserted into the document</a>.</p>
|
|
|
|
</dd></dl><p>When a user agent is to <dfn id="queue-a-task">queue a task</dfn>, it must add the
|
|
given task to one of the <a href="#task-queue" title="task queue">task queues</a>
|
|
of the relevant <a href="#event-loop">event loop</a>. All the tasks from one
|
|
particular <dfn id="task-source">task source</dfn> (e.g. the callbacks generated by
|
|
timers, the events dispatched for mouse movements, the tasks queued
|
|
for the parser) must always be added to the same <a href="#task-queue">task
|
|
queue</a>, but tasks from different <a href="#task-source" title="task
|
|
source">task sources</a> may be placed in different <a href="#task-queue" title="task queue">task queues</a>.</p>
|
|
|
|
<p class="example">For example, a user agent could have one
|
|
<a href="#task-queue">task queue</a> for mouse and key events (the <a href="#user-interaction-task-source">user
|
|
interaction task source</a>), and another for everything
|
|
else. The user agent could then give keyboard and mouse events
|
|
preference over other tasks three quarters of the time, keeping the
|
|
interface responsive but not starving other task queues, and never
|
|
processing events from any one <a href="#task-source">task source</a> out of
|
|
order.</p>
|
|
|
|
<p>Each <a href="#concept-task" title="concept-task">task</a> that is <a href="#queue-a-task" title="queue a task">queued</a> onto a <a href="#task-queue">task queue</a> of
|
|
an <a href="#event-loop">event loop</a> defined by this specification is
|
|
associated with a <code><a href="infrastructure.html#document">Document</a></code>; if the task was queued in
|
|
the context of an element, then it is the element's
|
|
<code><a href="infrastructure.html#document">Document</a></code>; if the task was queued in the context of a
|
|
<a href="browsers.html#browsing-context">browsing context</a>, then it is the <a href="browsers.html#browsing-context">browsing
|
|
context</a>'s <a href="browsers.html#active-document">active document</a> at the time the task
|
|
was queued; if the task was queued by or for a <a href="#concept-script" title="concept-script">script</a> then the document is the
|
|
<a href="#script-s-document">script's document</a>.</p>
|
|
|
|
<p>A user agent is required to have one <dfn id="storage-mutex">storage
|
|
mutex</dfn>. This mutex is used to control access to shared state
|
|
like cookies. At any one point, the <a href="#storage-mutex">storage mutex</a> is
|
|
either free, or owned by a particular <a href="#event-loop">event loop</a> or
|
|
instance of the <a href="fetching-resources.html#fetch" title="fetch">fetching</a> algorithm.</p>
|
|
|
|
<p>Whenever a <a href="#concept-script" title="concept-script">script</a> calls into
|
|
a <a href="infrastructure.html#plugin">plugin</a>, and whenever a <a href="infrastructure.html#plugin">plugin</a> calls into
|
|
a <a href="#concept-script" title="concept-script">script</a>, the user agent must
|
|
release the <a href="#storage-mutex">storage mutex</a>.</p>
|
|
|
|
|
|
<h5 id="processing-model-2"><span class="secno">6.1.4.2 </span>Processing model</h5>
|
|
|
|
<p>An <a href="#event-loop">event loop</a> must continually run through the
|
|
following steps for as long as it exists:</p>
|
|
|
|
<ol><li><p>Run the oldest <a href="#concept-task" title="concept-task">task</a> on one
|
|
of the <a href="#event-loop">event loop</a>'s <a href="#task-queue" title="task queue">task
|
|
queues</a>, ignoring tasks whose associated
|
|
<code><a href="infrastructure.html#document">Document</a></code>s are not <a href="browsers.html#fully-active">fully active</a>. The user
|
|
agent may pick any <a href="#task-queue">task queue</a>.</p></li>
|
|
|
|
|
|
<li><p>If the <a href="#storage-mutex">storage mutex</a> is now owned by the
|
|
<a href="#event-loop">event loop</a>, release it so that it is once again
|
|
free.</p></li>
|
|
|
|
<li><p>Remove that task from its <a href="#task-queue">task queue</a>.</p></li>
|
|
|
|
<li><p><a href="#provide-a-stable-state">Provide a stable state</a>.</p></li>
|
|
|
|
<li><p>If necessary, update the rendering or user interface of any
|
|
<code><a href="infrastructure.html#document">Document</a></code> or <a href="browsers.html#browsing-context">browsing context</a> to reflect
|
|
the current state.</p></li>
|
|
|
|
<li><p>Return to the first step of the <a href="#event-loop">event
|
|
loop</a>.</p></li>
|
|
|
|
</ol><hr><p>When the user agent is to <dfn id="provide-a-stable-state">provide a stable state</dfn>, if
|
|
any asynchronously-running algorithms are <dfn id="await-a-stable-state" title="await a stable
|
|
state">awaiting a stable state</dfn>, then the user agent must run
|
|
their <dfn id="synchronous-section">synchronous section</dfn> and then resume running their
|
|
asynchronous algorithm (if appropriate).</p>
|
|
|
|
<p class="note">A <a href="#synchronous-section">synchronous section</a> never mutates
|
|
the DOM, runs any script, or has any other side-effects.</p>
|
|
|
|
<p class="note">Steps in <a href="#synchronous-section" title="synchronous
|
|
section">synchronous sections</a> are marked with ⌛.</p>
|
|
|
|
<hr><p>When an algorithm says to <dfn id="spin-the-event-loop">spin the event loop</dfn> until
|
|
a condition <var title="">goal</var> is met, the user agent must run
|
|
the following steps:</p>
|
|
|
|
<ol><li><p>Let <var title="">task source</var> be the <a href="#task-source">task
|
|
source</a> of the currently running <a href="#concept-task" title="concept-task">task</a>.</p></li>
|
|
|
|
<li>
|
|
|
|
<p>Stop the currently running <a href="#concept-task" title="concept-task">task</a>, allowing the <a href="#event-loop">event
|
|
loop</a> to resume, but continue these steps
|
|
asynchronously.</p>
|
|
|
|
<p class="note">This causes the <a href="#event-loop">event loop</a> to move on
|
|
to the second step of its processing model (defined above).</p>
|
|
|
|
</li>
|
|
|
|
<li><p>Wait until the condition <var title="">goal</var> is
|
|
met.</p></li>
|
|
|
|
<li><p><a href="#queue-a-task">Queue a task</a> to continue running these steps,
|
|
using the <a href="#task-source">task source</a> <var title="">task
|
|
source</var>. Wait until this task runs before continuing these
|
|
steps.</p></li>
|
|
|
|
<li><p>Return to the caller.</p></li>
|
|
|
|
</ol><hr><p>Some of the algorithms in this specification, for historical
|
|
reasons, require the user agent to <dfn id="pause">pause</dfn> while running a
|
|
<a href="#concept-task" title="concept-task">task</a> until a condition <var title="">goal</var> is met. This means running the following
|
|
steps:</p>
|
|
|
|
<ol><li><p>If any asynchronously-running algorithms are <a href="#await-a-stable-state" title="await a stable state">awaiting a stable state</a>, then
|
|
run their <a href="#synchronous-section">synchronous section</a> and then resume running
|
|
their asynchronous algorithm. (See the <a href="#event-loop">event loop</a>
|
|
processing model definition above for details.)</p>
|
|
|
|
</li><li><p>If necessary, update the rendering or user interface of any
|
|
<code><a href="infrastructure.html#document">Document</a></code> or <a href="browsers.html#browsing-context">browsing context</a> to reflect
|
|
the current state.</p></li>
|
|
|
|
<li><p>Wait until the condition <var title="">goal</var> is met.
|
|
While a user agent has a paused <a href="#concept-task" title="concept-task">task</a>, the corresponding <a href="#event-loop">event
|
|
loop</a> must not run further <a href="#concept-task" title="concept-task">tasks</a>, and any script in the currently
|
|
running <a href="#concept-task" title="concept-task">task</a> must block. User
|
|
agents should remain responsive to user input while paused,
|
|
however, albeit in a reduced capacity since the <a href="#event-loop">event
|
|
loop</a> will not be doing anything.</p></li>
|
|
|
|
</ol><hr><p>When a user agent is to <dfn id="obtain-the-storage-mutex">obtain the storage mutex</dfn> as
|
|
part of running a <a href="#concept-task" title="concept-task">task</a>, it must
|
|
run through the following steps:</p>
|
|
|
|
<ol><li><p>If the <a href="#storage-mutex">storage mutex</a> is already owned by this
|
|
<a href="#concept-task" title="concept-task">task</a>'s <a href="#event-loop">event loop</a>,
|
|
then abort these steps.</p></li>
|
|
|
|
<li><p>Otherwise, <a href="#pause">pause</a> until the <a href="#storage-mutex">storage
|
|
mutex</a> can be taken by the <a href="#event-loop">event loop</a>.</p></li>
|
|
|
|
<li><p>Take ownership of the <a href="#storage-mutex">storage mutex</a>.</p></li>
|
|
|
|
</ol></div><div class="impl">
|
|
|
|
<h5 id="generic-task-sources"><span class="secno">6.1.4.3 </span>Generic task sources</h5>
|
|
|
|
<p>The following <a href="#task-source" title="task source">task sources</a> are
|
|
used by a number of mostly unrelated features in this and other
|
|
specifications.</p>
|
|
|
|
<dl><dt>The <dfn id="dom-manipulation-task-source">DOM manipulation task source</dfn></dt>
|
|
|
|
<dd>
|
|
|
|
<p>This <a href="#task-source">task source</a> is used for features that react
|
|
to DOM manipulations, such as things that happen asynchronously
|
|
when an element is <a href="infrastructure.html#insert-an-element-into-a-document" title="insert an element into a
|
|
document">inserted into the document</a>.</p>
|
|
|
|
|
|
</dd>
|
|
|
|
<dt>The <dfn id="user-interaction-task-source">user interaction task source</dfn></dt>
|
|
|
|
<dd>
|
|
|
|
<p>This <a href="#task-source">task source</a> is used for features that react
|
|
to user interaction, for example keyboard or mouse input.</p>
|
|
|
|
<p>Asynchronous events sent in response to user input (e.g. <code title="event-click"><a href="infrastructure.html#event-click">click</a></code> events) must be dispatched using
|
|
<a href="#concept-task" title="concept-task">tasks</a> <a href="#queue-a-task" title="queue a
|
|
task">queued</a> with the <a href="#user-interaction-task-source">user interaction task
|
|
source</a>. <a href="references.html#refsDOMEVENTS">[DOMEVENTS]</a></p>
|
|
|
|
</dd>
|
|
|
|
<dt>The <dfn id="networking-task-source">networking task source</dfn></dt>
|
|
|
|
<dd>
|
|
|
|
<p>This <a href="#task-source">task source</a> is used for features that trigger
|
|
in response to network activity.</p>
|
|
|
|
|
|
|
|
</dd>
|
|
|
|
<dt>The <dfn id="history-traversal-task-source">history traversal task source</dfn></dt>
|
|
|
|
<dd>
|
|
|
|
<p>This <a href="#task-source">task source</a> is used to queue calls to <code title="dom-history-back"><a href="history.html#dom-history-back">history.back()</a></code> and similar
|
|
APIs.</p>
|
|
|
|
</dd>
|
|
|
|
</dl></div><div class="impl">
|
|
|
|
<!-- SCRIPT EXEC -->
|
|
<h4 id="javascript-protocol"><span class="secno">6.1.5 </span><dfn title="javascript protocol">The <code title="">javascript:</code> URL scheme</dfn></h4>
|
|
|
|
<p>When a <a href="urls.html#url">URL</a> using the <code title="">javascript:</code> scheme is <dfn id="concept-js-deref" title="concept-js-deref">dereferenced</dfn>, the user agent must run
|
|
the following steps:</p>
|
|
|
|
<ol><li><p>Let the script source be the string obtained using the
|
|
content retrieval operation defined for <code title="">javascript:</code> URLs. <a href="references.html#refsJSURL">[JSURL]</a></p></li>
|
|
|
|
<li>
|
|
|
|
<p>Use the appropriate step from the following list:</p>
|
|
|
|
<dl><dt>If a <a href="browsers.html#browsing-context">browsing context</a> is being <a href="history.html#navigate" title="navigate">navigated</a> to a <code>javascript:</code>
|
|
URL, and the <a href="history.html#source-browsing-context">source browsing context</a> for that
|
|
navigation, if any, has <a href="#concept-bc-noscript" title="concept-bc-noscript">scripting disabled</a></dt>
|
|
|
|
<dd>
|
|
|
|
<p>Let <var title="">result</var> be void.</p>
|
|
|
|
</dd>
|
|
|
|
<dt>If a <a href="browsers.html#browsing-context">browsing context</a> is being <a href="history.html#navigate" title="navigate">navigated</a> to a <code>javascript:</code>
|
|
URL, and the <a href="browsers.html#active-document">active document</a> of that browsing
|
|
context has the <a href="origin-0.html#same-origin">same origin</a> as the script given by
|
|
that URL</dt>
|
|
|
|
<dd>
|
|
|
|
|
|
|
|
<p>Let <var title="">address</var> be the <a href="dom.html#the-document-s-address" title="the
|
|
document's address">address</a> of the <a href="browsers.html#active-document">active
|
|
document</a> of the <a href="browsers.html#browsing-context">browsing context</a> being
|
|
navigated.</p>
|
|
|
|
<p>If <var title="">address</var> is <code><a href="fetching-resources.html#about:blank">about:blank</a></code>,
|
|
and the <a href="browsers.html#browsing-context">browsing context</a> being navigated has a
|
|
<a href="browsers.html#creator-browsing-context">creator browsing context</a>, then let <var title="">address</var> be the <a href="dom.html#the-document-s-address" title="the document's
|
|
address">address</a> of the <a href="browsers.html#creator-document">creator
|
|
<code>Document</code></a> instead.</p>
|
|
|
|
<p><a href="#create-a-script-from-a-node" title="create a script from a node">Create a
|
|
script</a> from the <code><a href="infrastructure.html#document">Document</a></code> node of the
|
|
<a href="browsers.html#active-document">active document</a>, using the aforementioned script
|
|
source, and assuming the scripting language is JavaScript.</p>
|
|
|
|
<p>Let <var title="">result</var> be the return value of the
|
|
<i><a href="#initial-code-entry-point">initial code entry-point</a></i> of this <a href="#concept-script" title="concept-script">script</a>. If an exception was
|
|
raised, let <var title="">result</var> be void instead. (The
|
|
result will be void also if <a href="#concept-bc-noscript" title="concept-bc-noscript">scripting is disabled</a>.)</p>
|
|
|
|
<p>When it comes time to <a href="history.html#set-the-document-s-address">set the document's address</a>
|
|
in the <a href="history.html#navigate" title="navigate">navigation algorithm</a>, use
|
|
<var title="">address</var> as the <a href="history.html#override-url">override
|
|
URL</a>.</p>
|
|
|
|
</dd>
|
|
|
|
|
|
<dt>Otherwise</dt>
|
|
|
|
<dd>
|
|
|
|
<p>Let <var title="">result</var> be void.</p>
|
|
|
|
</dd>
|
|
|
|
</dl></li>
|
|
|
|
<li>
|
|
|
|
<p>If the result of executing the script is void (there is no
|
|
return value), then the URL must be treated in a manner equivalent
|
|
to an HTTP resource with an HTTP 204 No Content response.</p>
|
|
|
|
<p>Otherwise, the URL must be treated in a manner equivalent to an
|
|
HTTP resource with a 200 OK response whose <a href="fetching-resources.html#content-type" title="Content-Type">Content-Type metadata</a> is
|
|
<code><a href="iana.html#text-html">text/html</a></code> and whose response body is the return value
|
|
converted to a string value.</p>
|
|
|
|
<p class="note">Certain contexts, in particular <code><a href="embedded-content-1.html#the-img-element">img</a></code>
|
|
elements, ignore the <a href="fetching-resources.html#content-type" title="Content-Type">Content-Type
|
|
metadata</a>.</p>
|
|
|
|
</li>
|
|
|
|
</ol><div class="example">
|
|
|
|
<p>So for example a <code title="">javascript:</code> URL for a
|
|
<code title="attr-img-src"><a href="embedded-content-1.html#attr-img-src">src</a></code> attribute of an
|
|
<code><a href="embedded-content-1.html#the-img-element">img</a></code> element would be evaluated in the context of an
|
|
empty object as soon as the attribute is set; it would then be
|
|
sniffed to determine the image type and decoded as an image.</p>
|
|
|
|
<p>A <code title="">javascript:</code> URL in an <code title="attr-hyperlink-href"><a href="links.html#attr-hyperlink-href">href</a></code> attribute of an <code><a href="text-level-semantics.html#the-a-element">a</a></code>
|
|
element would only be evaluated when the link was <a href="links.html#following-hyperlinks" title="following hyperlinks">followed</a>.</p>
|
|
|
|
<p>The <code title="attr-iframe-src"><a href="the-iframe-element.html#attr-iframe-src">src</a></code> attribute of an
|
|
<code><a href="the-iframe-element.html#the-iframe-element">iframe</a></code> element would be evaluated in the context of
|
|
the <code><a href="the-iframe-element.html#the-iframe-element">iframe</a></code>'s own <a href="browsers.html#browsing-context">browsing context</a>; once
|
|
evaluated, its return value (if it was not void) would replace that
|
|
<a href="browsers.html#browsing-context">browsing context</a>'s document, thus changing the
|
|
variables visible in that <a href="browsers.html#browsing-context">browsing context</a>.</p>
|
|
|
|
</div>
|
|
|
|
</div><h4 id="events"><span class="secno">6.1.6 </span>Events</h4><div class="impl">
|
|
|
|
<h5 id="event-handler-attributes"><span class="secno">6.1.6.1 </span>Event handlers</h5>
|
|
|
|
</div><p>Many objects can have <dfn id="event-handlers">event handlers</dfn> specified. These
|
|
act as bubbling event listeners for the object on which they are
|
|
specified.</p><p>An <a href="#event-handlers" title="event handlers">event handler</a> can either
|
|
have the value null or be set to a <code><a href="#function">Function</a></code>
|
|
object. <span class="impl">Initially, event handlers must be set to
|
|
null.</span></p><p>Event handlers are exposed in one or two ways.</p><p>The first way, common to all event handlers, is as an <a href="#event-handler-idl-attributes" title="event handler IDL attributes">event handler IDL
|
|
attribute</a>.</p><p>The second way is as an <a href="#event-handler-content-attributes" title="event handler content
|
|
attributes">event handler content attribute</a>. Event handlers
|
|
on <a href="infrastructure.html#html-elements">HTML elements</a> and some of the event handlers on
|
|
<code><a href="browsers.html#window">Window</a></code> objects are exposed in this way.</p><div class="impl">
|
|
|
|
<hr><p><dfn id="event-handler-idl-attributes">Event handler IDL attributes</dfn>, on setting, must set the
|
|
corresponding event handler to their new value, and on
|
|
getting, must return whatever the current value of the corresponding
|
|
event handler is (possibly null).</p>
|
|
|
|
<p>If an <a href="#event-handler-idl-attributes" title="event handler IDL attributes">event handler
|
|
IDL attribute</a> exposes an <a href="#event-handlers" title="event handlers">event
|
|
handler</a> of an object that doesn't exist, it must always
|
|
return null on getting and must do nothing on setting.</p>
|
|
|
|
<p class="note">This can happen in particular for <a href="#event-handler-idl-attributes" title="event
|
|
handler IDL attributes">event handler IDL attribute</a> on
|
|
<code><a href="sections.html#the-body-element">body</a></code> elements that do not have corresponding
|
|
<code><a href="browsers.html#window">Window</a></code> objects.</p>
|
|
|
|
<p class="note">Certain event handler IDL attributes have additional
|
|
requirements, in particular the <code title="handler-MessagePort-onmessage">onmessage</code> attribute of
|
|
<code>MessagePort</code> objects.</p>
|
|
|
|
<hr></div><p><dfn id="event-handler-content-attributes">Event handler content attributes</dfn>, when specified, must
|
|
contain valid JavaScript code which, when parsed, would match the
|
|
<code title="">FunctionBody</code> production after automatic
|
|
semicolon insertion. <a href="references.html#refsECMA262">[ECMA262]</a></p><div class="impl">
|
|
|
|
<!-- SCRIPT EXEC -->
|
|
<p>When an <a href="#event-handler-content-attributes" title="event handler content attributes">event
|
|
handler content attribute</a> is set, if the element is owned by
|
|
a <code><a href="infrastructure.html#document">Document</a></code> that is in a <a href="browsers.html#browsing-context">browsing context</a>,
|
|
and <a href="#concept-bc-script" title="concept-bc-script">scripting is enabled</a> for
|
|
that <a href="browsers.html#browsing-context">browsing context</a>, the user agent must run the
|
|
following steps to create a <a href="#concept-script" title="concept-script">script</a> after setting the content
|
|
attribute to its new value:</p>
|
|
|
|
<ol><li><p>Set the corresponding <a href="#event-handlers" title="event handlers">event
|
|
handler</a> to null.</p></li>
|
|
|
|
<li><p>Set up a <a href="#script-execution-environment">script execution environment</a> for
|
|
JavaScript.</p></li>
|
|
|
|
<li><p>Let <var title="">body</var> be the <a href="#event-handler-content-attributes" title="event
|
|
handler content attributes">event handler content
|
|
attribute</a>'s new value.</p></li>
|
|
|
|
<li>
|
|
|
|
<p>If <var title="">body</var> is not parsable as
|
|
<i>FunctionBody</i> or if parsing detects an <i>early error</i>
|
|
then abort these steps.</p>
|
|
|
|
<p class="note"><i>FunctionBody</i> is defined in ECMAScript
|
|
edition 5 section 13 Function Definition. <i>Early error</i> is
|
|
defined in ECMAScript edition 5 section 16 Errors. <a href="references.html#refsECMA262">[ECMA262]</a></p>
|
|
|
|
</li>
|
|
|
|
<li>
|
|
|
|
<p>If <var title="">body</var> begins with a Directive Prologue
|
|
that contains a Use Strict Directive then let <var title="">strict</var> be true, otherwise let <var title="">strict</var> be false.</p>
|
|
<p class="note">The terms "Directive Prologue" and "Use Strict
|
|
Directive" are defined in ECMAScript edition 5 section 14.1
|
|
Directive Prologues and the Use Strict Directive. <a href="references.html#refsECMA262">[ECMA262]</a></p>
|
|
|
|
</li>
|
|
|
|
|
|
<li>
|
|
|
|
<p>Using the script execution environment created above, create a
|
|
function object (as defined in ECMAScript edition 5 section 13.2
|
|
Creating Function Objects), with:</p>
|
|
|
|
<dl><dt>Parameter list <var title="">FormalParameterList</var></dt>
|
|
|
|
<dd>
|
|
|
|
<dl class="switch"><dt>If the attribute is the <code title="handler-window-onerror"><a href="#handler-window-onerror">onerror</a></code> attribute of the
|
|
<code><a href="browsers.html#window">Window</a></code> object</dt>
|
|
|
|
<dd>Let the function have three arguments, named <code title="">event</code>, <code title="">source</code>, and <code title="">fileno</code>.</dd>
|
|
|
|
<dt>Otherwise</dt>
|
|
|
|
<dd>Let the function have a single argument called <code title="">event</code>.</dd>
|
|
|
|
</dl></dd>
|
|
|
|
<dt>Function body <var title="">FunctionBody</var></dt>
|
|
|
|
<dd>The result of parsing <var title="">body</var> above.</dd>
|
|
|
|
<dt>Lexical Environment <var title="">Scope</var></dt>
|
|
|
|
<dd>
|
|
|
|
<ol><li>Let <var title="">Scope</var> be the result of
|
|
NewObjectEnvironment(the element's <code><a href="infrastructure.html#document">Document</a></code>, the
|
|
<var title="">global environment</var>).</li>
|
|
|
|
<li>If the element has a <a href="association-of-controls-and-forms.html#form-owner">form owner</a>, let <var title="">Scope</var> be the result of NewObjectEnvironment(the
|
|
element's <a href="association-of-controls-and-forms.html#form-owner">form owner</a>, <var title="">Scope</var>).</li>
|
|
|
|
<li>Let <var title="">Scope</var> be the result of
|
|
NewObjectEnvironment(the element's object, <var title="">Scope</var>).</li>
|
|
|
|
</ol><p class="note">NewObjectEnvironment() is defined in ECMAScript
|
|
edition 5 section 10.2.2.3 NewObjectEnvironment (O, E). <a href="references.html#refsECMA262">[ECMA262]</a></p>
|
|
|
|
</dd>
|
|
|
|
<dt>Boolean flag <var title="">Strict</var></dt>
|
|
|
|
<dd>The value of <var title="">strict</var>.</dd>
|
|
|
|
</dl><p>Let this new function be the only entry in the script's
|
|
<a href="#list-of-code-entry-points">list of code entry-points</a>.</p>
|
|
|
|
</li>
|
|
|
|
<li><p>Set up the <a href="#script-s-global-object">script's global object</a>, the
|
|
<a href="#script-s-browsing-context">script's browsing context</a>, the <a href="#script-s-document">script's
|
|
document</a>, the <a href="#script-s-url-character-encoding">script's URL character encoding</a>,
|
|
and the <a href="#script-s-base-url">script's base URL</a> from <a href="#the-script-settings-determined-from-the-node">the script
|
|
settings determined from the node</a> on which the attribute is
|
|
being set.</p></li>
|
|
|
|
<li><p>Set the corresponding <a href="#event-handlers" title="event handlers">event
|
|
handler</a> to the aforementioned function.</p></li>
|
|
|
|
</ol><p>When an event handler content attribute is removed, the user
|
|
agent must set the corresponding <a href="#event-handlers" title="event handlers">event
|
|
handler</a> to null.</p>
|
|
|
|
</div><p class="note">When an <a href="#event-handler-content-attributes" title="event handler content
|
|
attributes">event handler content attribute</a> is set on an
|
|
element owned by a <code><a href="infrastructure.html#document">Document</a></code> that is not in a
|
|
<a href="browsers.html#browsing-context">browsing context</a>, the corresponding event handler is
|
|
not changed.</p><div class="impl">
|
|
|
|
<hr><p>All <a href="#event-handlers">event handlers</a> on an object, whether an element
|
|
or some other object, and whether set to null or to a
|
|
<code><a href="#function">Function</a></code> object, must be registered as event listeners
|
|
on the object when it is created, as if the <code title="dom-EventTarget-addEventListener">addEventListener()</code>
|
|
method on the object's <code><a href="infrastructure.html#eventtarget">EventTarget</a></code> interface had been
|
|
invoked, with the event type (<var title="dom-event-type">type</var>
|
|
argument) equal to the type corresponding to the event handler (the
|
|
<dfn id="event-handler-event-type">event handler event type</dfn>), the listener set to be a
|
|
target and bubbling phase listener (<var title="dom-event-useCapture">useCapture</var> argument set to
|
|
false), and the event listener itself (<var title="dom-event-listener">listener</var> argument) set to do
|
|
nothing while the event handler's value is not a
|
|
<code><a href="#function">Function</a></code> object, and set to invoke the <code title="dom-function-call"><a href="#dom-function-call">call()</a></code> callback of the
|
|
<code><a href="#function">Function</a></code> object associated with the event handler
|
|
otherwise.</p>
|
|
|
|
</div><p class="note"><a href="#event-handlers">Event handlers</a> <span class="impl">therefore</span> always fire before event listeners
|
|
attached using <code title="dom-EventTarget-addEventListener">addEventListener()</code>.</p><div class="impl">
|
|
|
|
<p class="note">The <var title="dom-event-listener">listener</var>
|
|
argument is emphatically <em>not</em> the <a href="#event-handlers" title="event
|
|
handlers">event handler</a> itself.</p>
|
|
|
|
<p class="note">The interfaces implemented by the event object do
|
|
not influence whether an <a href="#event-handlers" title="event handlers">event
|
|
handler</a> is triggered or not.</p>
|
|
|
|
<p>When an <a href="#event-handlers" title="event handlers">event handler</a>'s
|
|
<code><a href="#function">Function</a></code> object is invoked, its <code title="dom-function-call"><a href="#dom-function-call">call()</a></code> callback must be invoked
|
|
with one argument, set to the <code><a href="infrastructure.html#event">Event</a></code> object of the event
|
|
in question.</p>
|
|
|
|
<p>The handler's return value must then be processed as follows:</p>
|
|
|
|
<dl class="switch"><dt>If the event type is <code class="event-mouseover">mouseover</code></dt>
|
|
|
|
<dd><p>If the return value is a boolean with the value true, then
|
|
the event must be canceled.</p></dd>
|
|
|
|
<dt>If the event object is a <code><a href="history.html#beforeunloadevent">BeforeUnloadEvent</a></code> object</dt>
|
|
|
|
<dd><p>If the return value is a string, and the event object's
|
|
<code title="dom-BeforeUnloadEvent-returnValue"><a href="history.html#dom-beforeunloadevent-returnvalue">returnValue</a></code>
|
|
attribute's value is the empty string, then set the <code title="dom-BeforeUnloadEvent-returnValue"><a href="history.html#dom-beforeunloadevent-returnvalue">returnValue</a></code>
|
|
attribute's value to the return value.</p></dd>
|
|
|
|
<dt>Otherwise</dt>
|
|
|
|
<dd><p>If the return value is a boolean with the value false, then
|
|
the event must be canceled.</p></dd>
|
|
|
|
</dl></div><hr><p>The <code><a href="#function">Function</a></code> interface represents a function in the
|
|
scripting language being used. It is represented in IDL as
|
|
follows:</p><pre class="idl">[Callback=FunctionOnly, NoInterfaceObject]
|
|
interface <dfn id="function">Function</dfn> {
|
|
any <a href="#dom-function-call" title="dom-function-call">call</a>(in any... arguments);
|
|
};</pre><p>The <dfn id="dom-function-call" title="dom-function-call"><code>call(...)</code></dfn>
|
|
method is the object's callback.</p><p class="note">In JavaScript, any <code title="">Function</code>
|
|
object implements this interface.</p><p>If the <code><a href="#function">Function</a></code> object is a JavaScript <code title="">Function</code>, then when it is invoked by the user agent,
|
|
the user agent must set the <var title="">thisArg</var> (as defined
|
|
by ECMAScript edition 5 section 10.4.3 Entering Function Code) to
|
|
the <a href="#event-handlers" title="event handlers">event handler</a>'s object. <a href="references.html#refsECMA262">[ECMA262]</a></p><div class="example">
|
|
|
|
<p>For example, the following document fragment:</p>
|
|
|
|
<pre><body onload="alert(this)" onclick="alert(this)"></pre>
|
|
|
|
<p>...leads to an alert saying "<code title="">[object Window]</code>" when the document is loaded,
|
|
and an alert saying "<code title="">[object HTMLBodyElement]</code>" whenever the user
|
|
clicks something in the page.</p>
|
|
|
|
</div><p>The return value of the function affects whether the event is
|
|
canceled or not: <span class="impl">as described above,</span> if
|
|
the return value is false, the event is canceled (except for <code class="event-mouseover">mouseover</code> events, where the return
|
|
value has to be true to cancel the event). With <code title="event-beforeunload">beforeunload</code> events, the value is
|
|
instead used to determine the message to show the user.</p><div class="impl">
|
|
|
|
<h5 id="event-handlers-on-elements-document-objects-and-window-objects"><span class="secno">6.1.6.2 </span>Event handlers on elements, <code><a href="infrastructure.html#document">Document</a></code> objects, and <code><a href="browsers.html#window">Window</a></code> objects</h5>
|
|
|
|
<p>The following are the <a href="#event-handlers">event handlers</a> (and their
|
|
corresponding <a href="#event-handler-event-type" title="event handler event type">event handler
|
|
event types</a>) that must be supported by all <a href="infrastructure.html#html-elements">HTML
|
|
elements</a>, as both content attributes and IDL attributes, and
|
|
on <code><a href="infrastructure.html#document">Document</a></code> and <code><a href="browsers.html#window">Window</a></code> objects, as IDL
|
|
attributes.</p>
|
|
|
|
<table><thead><tr><th><a href="#event-handlers" title="event handlers">Event handler</a> </th><th><a href="#event-handler-event-type">Event handler event type</a>
|
|
</th></tr></thead><tbody><tr><td><dfn id="handler-onabort" title="handler-onabort"><code>onabort</code></dfn> </td><td> <code title="event-abort">abort</code>
|
|
</td></tr><tr><td><dfn id="handler-oncanplay" title="handler-oncanplay"><code>oncanplay</code></dfn> </td><td> <code title="event-media-canplay"><a href="the-iframe-element.html#event-media-canplay">canplay</a></code>
|
|
</td></tr><tr><td><dfn id="handler-oncanplaythrough" title="handler-oncanplaythrough"><code>oncanplaythrough</code></dfn> </td><td> <code title="event-media-canplaythrough"><a href="the-iframe-element.html#event-media-canplaythrough">canplaythrough</a></code>
|
|
</td></tr><tr><td><dfn id="handler-onchange" title="handler-onchange"><code>onchange</code></dfn> </td><td> <code title="event-change">change</code>
|
|
</td></tr><tr><td><dfn id="handler-onclick" title="handler-onclick"><code>onclick</code></dfn> </td><td> <code title="event-click"><a href="infrastructure.html#event-click">click</a></code>
|
|
</td></tr><tr><td><dfn id="handler-oncontextmenu" title="handler-oncontextmenu"><code>oncontextmenu</code></dfn> </td><td> <code title="event-contextmenu">contextmenu</code>
|
|
</td></tr><tr><td><dfn id="handler-oncuechange" title="handler-oncuechange"><code>oncuechange</code></dfn> </td><td> <code title="event-cuechange">cuechange</code>
|
|
</td></tr><tr><td><dfn id="handler-ondblclick" title="handler-ondblclick"><code>ondblclick</code></dfn> </td><td> <code title="event-dblclick">dblclick</code>
|
|
</td></tr><tr><td><dfn id="handler-ondrag" title="handler-ondrag"><code>ondrag</code></dfn> </td><td> <code title="event-drag"><a href="dnd.html#event-drag">drag</a></code>
|
|
</td></tr><tr><td><dfn id="handler-ondragend" title="handler-ondragend"><code>ondragend</code></dfn> </td><td> <code title="event-dragend"><a href="dnd.html#event-dragend">dragend</a></code>
|
|
</td></tr><tr><td><dfn id="handler-ondragenter" title="handler-ondragenter"><code>ondragenter</code></dfn> </td><td> <code title="event-dragenter"><a href="dnd.html#event-dragenter">dragenter</a></code>
|
|
</td></tr><tr><td><dfn id="handler-ondragleave" title="handler-ondragleave"><code>ondragleave</code></dfn> </td><td> <code title="event-dragleave"><a href="dnd.html#event-dragleave">dragleave</a></code>
|
|
</td></tr><tr><td><dfn id="handler-ondragover" title="handler-ondragover"><code>ondragover</code></dfn> </td><td> <code title="event-dragover"><a href="dnd.html#event-dragover">dragover</a></code>
|
|
</td></tr><tr><td><dfn id="handler-ondragstart" title="handler-ondragstart"><code>ondragstart</code></dfn> </td><td> <code title="event-dragstart"><a href="dnd.html#event-dragstart">dragstart</a></code>
|
|
</td></tr><tr><td><dfn id="handler-ondrop" title="handler-ondrop"><code>ondrop</code></dfn> </td><td> <code title="event-drop"><a href="dnd.html#event-drop">drop</a></code>
|
|
</td></tr><tr><td><dfn id="handler-ondurationchange" title="handler-ondurationchange"><code>ondurationchange</code></dfn> </td><td> <code title="event-media-durationchange"><a href="the-iframe-element.html#event-media-durationchange">durationchange</a></code>
|
|
</td></tr><tr><td><dfn id="handler-onemptied" title="handler-onemptied"><code>onemptied</code></dfn> </td><td> <code title="event-media-emptied"><a href="the-iframe-element.html#event-media-emptied">emptied</a></code>
|
|
</td></tr><tr><td><dfn id="handler-onended" title="handler-onended"><code>onended</code></dfn> </td><td> <code title="event-media-ended"><a href="the-iframe-element.html#event-media-ended">ended</a></code>
|
|
</td></tr><tr><td><dfn id="handler-oninput" title="handler-oninput"><code>oninput</code></dfn> </td><td> <code title="event-input">input</code>
|
|
</td></tr><tr><td><dfn id="handler-oninvalid" title="handler-oninvalid"><code>oninvalid</code></dfn> </td><td> <code title="event-invalid">invalid</code>
|
|
</td></tr><tr><td><dfn id="handler-onkeydown" title="handler-onkeydown"><code>onkeydown</code></dfn> </td><td> <code title="event-keydown">keydown</code>
|
|
</td></tr><tr><td><dfn id="handler-onkeypress" title="handler-onkeypress"><code>onkeypress</code></dfn> </td><td> <code title="event-keypress">keypress</code>
|
|
</td></tr><tr><td><dfn id="handler-onkeyup" title="handler-onkeyup"><code>onkeyup</code></dfn> </td><td> <code title="event-keyup">keyup</code>
|
|
</td></tr><tr><td><dfn id="handler-onloadeddata" title="handler-onloadeddata"><code>onloadeddata</code></dfn> </td><td> <code title="event-media-loadeddata"><a href="the-iframe-element.html#event-media-loadeddata">loadeddata</a></code>
|
|
</td></tr><tr><td><dfn id="handler-onloadedmetadata" title="handler-onloadedmetadata"><code>onloadedmetadata</code></dfn> </td><td> <code title="event-media-loadedmetadata"><a href="the-iframe-element.html#event-media-loadedmetadata">loadedmetadata</a></code>
|
|
</td></tr><tr><td><dfn id="handler-onloadstart" title="handler-onloadstart"><code>onloadstart</code></dfn> </td><td> <code title="event-media-loadstart"><a href="the-iframe-element.html#event-media-loadstart">loadstart</a></code>
|
|
</td></tr><tr><td><dfn id="handler-onmousedown" title="handler-onmousedown"><code>onmousedown</code></dfn> </td><td> <code title="event-mousedown">mousedown</code>
|
|
</td></tr><tr><td><dfn id="handler-onmousemove" title="handler-onmousemove"><code>onmousemove</code></dfn> </td><td> <code title="event-mousemove">mousemove</code>
|
|
</td></tr><tr><td><dfn id="handler-onmouseout" title="handler-onmouseout"><code>onmouseout</code></dfn> </td><td> <code title="event-mouseout">mouseout</code>
|
|
</td></tr><tr><td><dfn id="handler-onmouseover" title="handler-onmouseover"><code>onmouseover</code></dfn> </td><td> <code title="event-mouseover">mouseover</code>
|
|
</td></tr><tr><td><dfn id="handler-onmouseup" title="handler-onmouseup"><code>onmouseup</code></dfn> </td><td> <code title="event-mouseup">mouseup</code>
|
|
</td></tr><tr><td><dfn id="handler-onmousewheel" title="handler-onmousewheel"><code>onmousewheel</code></dfn> </td><td> <code title="event-mousewheel">mousewheel</code>
|
|
</td></tr><tr><td><dfn id="handler-onpause" title="handler-onpause"><code>onpause</code></dfn> </td><td> <code title="event-media-pause"><a href="the-iframe-element.html#event-media-pause">pause</a></code>
|
|
</td></tr><tr><td><dfn id="handler-onplay" title="handler-onplay"><code>onplay</code></dfn> </td><td> <code title="event-media-play"><a href="the-iframe-element.html#event-media-play">play</a></code>
|
|
</td></tr><tr><td><dfn id="handler-onplaying" title="handler-onplaying"><code>onplaying</code></dfn> </td><td> <code title="event-media-playing"><a href="the-iframe-element.html#event-media-playing">playing</a></code>
|
|
</td></tr><tr><td><dfn id="handler-onprogress" title="handler-onprogress"><code>onprogress</code></dfn> </td><td> <code title="event-media-progress"><a href="the-iframe-element.html#event-media-progress">progress</a></code>
|
|
</td></tr><tr><td><dfn id="handler-onratechange" title="handler-onratechange"><code>onratechange</code></dfn> </td><td> <code title="event-media-ratechange"><a href="the-iframe-element.html#event-media-ratechange">ratechange</a></code>
|
|
</td></tr><tr><td><dfn id="handler-onreadystatechange" title="handler-onreadystatechange"><code>onreadystatechange</code></dfn> </td><td> <code title="event-readystatechange"><a href="dom.html#event-readystatechange">readystatechange</a></code>
|
|
</td></tr><tr><td><dfn id="handler-onreset" title="handler-onreset"><code>onreset</code></dfn> </td><td> <code title="event-reset">reset</code>
|
|
</td></tr><tr><td><dfn id="handler-onseeked" title="handler-onseeked"><code>onseeked</code></dfn> </td><td> <code title="event-media-seeked"><a href="the-iframe-element.html#event-media-seeked">seeked</a></code>
|
|
</td></tr><tr><td><dfn id="handler-onseeking" title="handler-onseeking"><code>onseeking</code></dfn> </td><td> <code title="event-media-seeking"><a href="the-iframe-element.html#event-media-seeking">seeking</a></code>
|
|
</td></tr><tr><td><dfn id="handler-onselect" title="handler-onselect"><code>onselect</code></dfn> </td><td> <code title="event-select">select</code> <!-- [CSSOM] -->
|
|
</td></tr><tr><td><dfn id="handler-onshow" title="handler-onshow"><code>onshow</code></dfn> </td><td> <code title="event-show">show</code>
|
|
</td></tr><tr><td><dfn id="handler-onstalled" title="handler-onstalled"><code>onstalled</code></dfn> </td><td> <code title="event-media-stalled"><a href="the-iframe-element.html#event-media-stalled">stalled</a></code>
|
|
</td></tr><tr><td><dfn id="handler-onsubmit" title="handler-onsubmit"><code>onsubmit</code></dfn> </td><td> <code title="event-submit">submit</code>
|
|
</td></tr><tr><td><dfn id="handler-onsuspend" title="handler-onsuspend"><code>onsuspend</code></dfn> </td><td> <code title="event-media-suspend"><a href="the-iframe-element.html#event-media-suspend">suspend</a></code>
|
|
</td></tr><tr><td><dfn id="handler-ontimeupdate" title="handler-ontimeupdate"><code>ontimeupdate</code></dfn> </td><td> <code title="event-media-timeupdate"><a href="the-iframe-element.html#event-media-timeupdate">timeupdate</a></code>
|
|
</td></tr><tr><td><dfn id="handler-onvolumechange" title="handler-onvolumechange"><code>onvolumechange</code></dfn> </td><td> <code title="event-media-volumechange"><a href="the-iframe-element.html#event-media-volumechange">volumechange</a></code>
|
|
</td></tr><tr><td><dfn id="handler-onwaiting" title="handler-onwaiting"><code>onwaiting</code></dfn> </td><td> <code title="event-media-waiting"><a href="the-iframe-element.html#event-media-waiting">waiting</a></code>
|
|
|
|
|
|
|
|
|
|
|
|
</td></tr></tbody></table><hr><p>The following are the <a href="#event-handlers">event handlers</a> (and their
|
|
corresponding <a href="#event-handler-event-type" title="event handler event type">event handler
|
|
event types</a>) that must be supported by all <a href="infrastructure.html#html-elements">HTML
|
|
elements</a> other than <code><a href="sections.html#the-body-element">body</a></code>, as both content
|
|
attributes and IDL attributes, and on <code><a href="infrastructure.html#document">Document</a></code> objects,
|
|
as IDL attributes:</p>
|
|
|
|
<table><thead><tr><th><a href="#event-handlers" title="event handlers">Event handler</a> </th><th><a href="#event-handler-event-type">Event handler event type</a>
|
|
</th></tr></thead><tbody><tr><td><dfn id="handler-onblur" title="handler-onblur"><code>onblur</code></dfn> </td><td> <code title="event-blur">blur</code>
|
|
</td></tr><tr><td><dfn id="handler-onerror" title="handler-onerror"><code>onerror</code></dfn> </td><td> <code title="event-error">error</code>
|
|
</td></tr><tr><td><dfn id="handler-onfocus" title="handler-onfocus"><code>onfocus</code></dfn> </td><td> <code title="event-focus">focus</code>
|
|
</td></tr><tr><td><dfn id="handler-onload" title="handler-onload"><code>onload</code></dfn> </td><td> <code title="event-load">load</code>
|
|
</td></tr><tr><td><dfn id="handler-onscroll" title="handler-onscroll"><code>onscroll</code></dfn> </td><td> <code title="event-scroll">scroll</code>
|
|
</td></tr></tbody></table><hr><p>The following are the <a href="#event-handlers">event handlers</a> (and their
|
|
corresponding <a href="#event-handler-event-type" title="event handler event type">event handler
|
|
event types</a>) that must be supported by <code><a href="browsers.html#window">Window</a></code>
|
|
objects, as IDL attributes on the <code><a href="browsers.html#window">Window</a></code> object, and
|
|
with corresponding content attributes and IDL attributes exposed on
|
|
the <code><a href="sections.html#the-body-element">body</a></code> and <code><a href="obsolete.html#frameset">frameset</a></code> elements:</p>
|
|
|
|
<table><thead><tr><th><a href="#event-handlers" title="event handlers">Event handler</a> </th><th><a href="#event-handler-event-type">Event handler event type</a>
|
|
</th></tr></thead><tbody><tr><td><dfn id="handler-window-onafterprint" title="handler-window-onafterprint"><code>onafterprint</code></dfn> </td><td> <code title="event-afterprint">afterprint</code>
|
|
</td></tr><tr><td><dfn id="handler-window-onbeforeprint" title="handler-window-onbeforeprint"><code>onbeforeprint</code></dfn> </td><td> <code title="event-beforeprint">beforeprint</code>
|
|
</td></tr><tr><td><dfn id="handler-window-onbeforeunload" title="handler-window-onbeforeunload"><code>onbeforeunload</code></dfn> </td><td> <code title="event-beforeunload">beforeunload</code>
|
|
</td></tr><tr><td><dfn id="handler-window-onblur" title="handler-window-onblur"><code>onblur</code></dfn> </td><td> <code title="event-blur">blur</code>
|
|
</td></tr><tr><td><dfn id="handler-window-onerror" title="handler-window-onerror"><code>onerror</code></dfn> </td><td> <code title="event-error">error</code>
|
|
</td></tr><tr><td><dfn id="handler-window-onfocus" title="handler-window-onfocus"><code>onfocus</code></dfn> </td><td> <code title="event-focus">focus</code>
|
|
</td></tr><tr><td><dfn id="handler-window-onhashchange" title="handler-window-onhashchange"><code>onhashchange</code></dfn> </td><td> <code title="event-hashchange"><a href="history.html#event-hashchange">hashchange</a></code>
|
|
</td></tr><tr><td><dfn id="handler-window-onload" title="handler-window-onload"><code>onload</code></dfn> </td><td> <code title="event-load">load</code>
|
|
</td></tr><tr><td><dfn id="handler-window-onmessage" title="handler-window-onmessage"><code>onmessage</code></dfn> </td><td> <code title="event-message">message</code>
|
|
</td></tr><tr><td><dfn id="handler-window-onoffline" title="handler-window-onoffline"><code>onoffline</code></dfn> </td><td> <code title="event-offline"><a href="offline.html#event-offline">offline</a></code>
|
|
</td></tr><tr><td><dfn id="handler-window-ononline" title="handler-window-ononline"><code>ononline</code></dfn> </td><td> <code title="event-online"><a href="offline.html#event-online">online</a></code>
|
|
</td></tr><tr><td><dfn id="handler-window-onpagehide" title="handler-window-onpagehide"><code>onpagehide</code></dfn> </td><td> <code title="event-pagehide"><a href="history.html#event-pagehide">pagehide</a></code>
|
|
</td></tr><tr><td><dfn id="handler-window-onpageshow" title="handler-window-onpageshow"><code>onpageshow</code></dfn> </td><td> <code title="event-pageshow"><a href="history.html#event-pageshow">pageshow</a></code>
|
|
</td></tr><tr><td><dfn id="handler-window-onpopstate" title="handler-window-onpopstate"><code>onpopstate</code></dfn> </td><td> <code title="event-popstate"><a href="history.html#event-popstate">popstate</a></code>
|
|
</td></tr><tr><td><dfn id="handler-window-onredo" title="handler-window-onredo"><code>onredo</code></dfn> </td><td> <code title="event-redo">redo</code>
|
|
</td></tr><tr><td><dfn id="handler-window-onresize" title="handler-window-onresize"><code>onresize</code></dfn> </td><td> <code title="event-resize">resize</code> <!-- [CSSOM] -->
|
|
</td></tr><tr><td><dfn id="handler-window-onscroll" title="handler-window-onscroll"><code>onscroll</code></dfn> </td><td> <code title="event-scroll">scroll</code>
|
|
</td></tr><tr><td><dfn id="handler-window-onstorage" title="handler-window-onstorage"><code>onstorage</code></dfn> </td><td> <code title="event-storage">storage</code>
|
|
</td></tr><tr><td><dfn id="handler-window-onundo" title="handler-window-onundo"><code>onundo</code></dfn> </td><td> <code title="event-undo">undo</code>
|
|
</td></tr><tr><td><dfn id="handler-window-onunload" title="handler-window-onunload"><code>onunload</code></dfn> </td><td> <code title="event-unload">unload</code>
|
|
</td></tr></tbody></table><p class="note">The <code title="handler-window-onerror"><a href="#handler-window-onerror">onerror</a></code>
|
|
handler is also used for <a href="#runtime-script-errors">reporting script errors</a>.</p>
|
|
|
|
</div><div class="impl">
|
|
|
|
<h5 id="event-firing"><span class="secno">6.1.6.3 </span>Event firing</h5>
|
|
|
|
<p>Certain operations and methods are defined as firing events on
|
|
elements. For example, the <code title="dom-click"><a href="editing.html#dom-click">click()</a></code>
|
|
method on the <code><a href="elements.html#htmlelement">HTMLElement</a></code> interface is defined as
|
|
firing a <code title="event-click"><a href="infrastructure.html#event-click">click</a></code> event on the
|
|
element. <a href="references.html#refsDOMEVENTS">[DOMEVENTS]</a></p>
|
|
|
|
<p><dfn id="fire-a-simple-event" title="fire a simple event">Firing a simple event named <var title="">e</var></dfn> means that an event with the name <var title="">e</var>, which does not bubble (except where otherwise
|
|
stated) and is not cancelable (except where otherwise stated), and
|
|
which uses the <code><a href="infrastructure.html#event">Event</a></code> interface, must be dispatched at
|
|
the given target.</p>
|
|
|
|
<p><dfn id="fire-a-synthetic-mouse-event" title="fire a synthetic mouse event">Firing a synthetic
|
|
mouse event named <var title="">e</var></dfn> means that an event
|
|
with the name <var title="">e</var>, which does not bubble (except
|
|
where otherwise stated) and is not cancelable (except where
|
|
otherwise stated), and which uses the <code><a href="infrastructure.html#mouseevent">MouseEvent</a></code>
|
|
interface, must be dispatched at the given target. The event object
|
|
must have its <code title="">screenX</code>, <code title="">screenY</code>, <code title="">clientX</code>, <code title="">clientY</code>, and <code title="">button</code> attributes
|
|
set to 0, its <code title="">ctrlKey</code>, <code title="">shiftKey</code>, <code title="">altKey</code>, and <code title="">metaKey</code> attributes set according to the current
|
|
state of the key input device, if any (false for any keys that are
|
|
not available), its <code title="">detail</code> attribute set to 1,
|
|
and its <code title="">relatedTarget</code> attribute set to null.
|
|
The <code title="">getModifierState()</code> method on the object
|
|
must return values appropriately describing the state of the key
|
|
input device at the time the event is created.</p>
|
|
|
|
<p><dfn id="fire-a-click-event" title="fire a click event">Firing a <code title="event-click">click</code> event</dfn> means <a href="#fire-a-synthetic-mouse-event" title="fire
|
|
a synthetic mouse event">firing a synthetic mouse event named <code title="event-click">click</code></a>, which bubbles and is
|
|
cancelable.</p>
|
|
|
|
<p>The default action of these events is to do nothing except where
|
|
otherwise stated.</p>
|
|
|
|
</div><div class="impl">
|
|
|
|
<h5 id="events-and-the-window-object"><span class="secno">6.1.6.4 </span>Events and the <code><a href="browsers.html#window">Window</a></code> object</h5>
|
|
|
|
<p>When an event is dispatched at a DOM node in a
|
|
<code><a href="infrastructure.html#document">Document</a></code> in a <a href="browsers.html#browsing-context">browsing context</a>, if the
|
|
event is not a <code title="event-load">load</code> event, the user
|
|
agent must also dispatch the event to the <code><a href="browsers.html#window">Window</a></code>, as
|
|
follows:</p>
|
|
|
|
<ol><li>In the capture phase, the event must propagate to the
|
|
<code><a href="browsers.html#window">Window</a></code> object before propagating to any of the nodes,
|
|
as if the <code><a href="browsers.html#window">Window</a></code> object was the parent of the
|
|
<code><a href="infrastructure.html#document">Document</a></code> in the dispatch chain.</li>
|
|
|
|
<li>In the bubble phase, the event must propagate up to the
|
|
<code><a href="browsers.html#window">Window</a></code> object at the end of the phase, unless bubbling
|
|
has been prevented, again as if the <code><a href="browsers.html#window">Window</a></code> object was
|
|
the parent of the <code><a href="infrastructure.html#document">Document</a></code> in the dispatch chain.</li>
|
|
|
|
</ol></div><h3 id="atob"><span class="secno">6.2 </span>Base64 utility methods</h3><p>The <code title="dom-windowbase64-atob"><a href="#dom-windowbase64-atob">atob()</a></code> and <code title="dom-windowbase64-btoa"><a href="#dom-windowbase64-btoa">btoa()</a></code> methods allow authors to
|
|
transform content to and from the base64 encoding.</p><pre class="idl">[Supplemental, NoInterfaceObject]
|
|
interface <dfn id="windowbase64">WindowBase64</dfn> {
|
|
DOMString <a href="#dom-windowbase64-btoa" title="dom-windowbase64-btoa">btoa</a>(in DOMString btoa);
|
|
DOMString <a href="#dom-windowbase64-atob" title="dom-windowbase64-atob">atob</a>(in DOMString atob);
|
|
};
|
|
<a href="browsers.html#window">Window</a> implements <a href="#windowbase64">WindowBase64</a>;</pre><p class="note">In these APIs, for mnemonic purposes, the "b" can be
|
|
considered to stand for "binary", and the "a" for "ASCII". In
|
|
practice, though, for primarily historical reasons, both the input
|
|
and output of these functions are Unicode strings.</p><dl class="domintro"><dt><var title="">result</var> = <var title="">window</var> . <code title="dom-windowbase64-btoa"><a href="#dom-windowbase64-btoa">btoa</a></code>( <var title="">data</var> )</dt>
|
|
|
|
<dd>
|
|
|
|
<p>Takes the input data, in the form of a Unicode string
|
|
containing only characters in the range U+0000 to U+00FF, each
|
|
representing a binary byte with values 0x00 to 0xFF respectively,
|
|
and converts it to its base64 representation, which it returns.</p>
|
|
|
|
<p>Throws an <code><a href="common-dom-interfaces.html#invalid_character_err">INVALID_CHARACTER_ERR</a></code> exception if the
|
|
input string contains any out-of-range characters.</p>
|
|
|
|
</dd>
|
|
|
|
<dt><var title="">result</var> = <var title="">window</var> . <code title="dom-windowbase64-atob"><a href="#dom-windowbase64-atob">atob</a></code>( <var title="">data</var> )</dt>
|
|
|
|
<dd>
|
|
|
|
<p>Takes the input data, in the form of a Unicode string
|
|
containing base64-encoded binary data, decodes it, and returns a
|
|
string consisting of characters in the range U+0000 to U+00FF,
|
|
each representing a binary byte with values 0x00 to 0xFF
|
|
respectively, corresponding to that binary data.</p>
|
|
|
|
<p>Throws an <code><a href="common-dom-interfaces.html#invalid_character_err">INVALID_CHARACTER_ERR</a></code> exception if the
|
|
input string is not valid base64 data.</p>
|
|
|
|
</dd>
|
|
|
|
</dl><div class="impl">
|
|
|
|
<p class="note">The <code><a href="#windowbase64">WindowBase64</a></code> interface adds to the
|
|
<code><a href="browsers.html#window">Window</a></code> interface and the <code>WorkerUtils</code>
|
|
interface (part of Web Workers).</p>
|
|
|
|
<p>The <dfn id="dom-windowbase64-btoa" title="dom-windowbase64-btoa"><code>btoa()</code></dfn>
|
|
method must throw an <code><a href="common-dom-interfaces.html#invalid_character_err">INVALID_CHARACTER_ERR</a></code> exception if
|
|
the method's first argument contains any character whose code point
|
|
is greater than U+00FF. Otherwise, the user agent must convert that
|
|
argument to a sequence of octets whose <var title="">n</var>th octet
|
|
is the eight-bit representation of the code point of the <var title="">n</var>th character of the argument, and then must apply
|
|
the base64 algorithm to that sequence of octets, and return the
|
|
result. <a href="references.html#refsRFC4648">[RFC4648]</a></p>
|
|
|
|
|
|
<p>The <dfn id="dom-windowbase64-atob" title="dom-windowbase64-atob"><code>atob()</code></dfn>
|
|
method must run the following steps to parse the string passed in
|
|
the method's first argument:</p>
|
|
|
|
<ol><li><p>Let <var title="">input</var> be the string being
|
|
parsed.</p></li>
|
|
|
|
<li><p>Let <var title="">position</var> be a pointer into <var title="">input</var>, initially pointing at the start of the
|
|
string.</p></li>
|
|
|
|
<li><p>If the length of <var title="">input</var> divides by 4
|
|
leaving no remainder, then: if <var title="">input</var> ends with
|
|
one or two U+003D EQUALS SIGN (=) characters, remove them from <var title="">input</var>.</p></li>
|
|
|
|
<li><p>If the length of <var title="">input</var> divides by 4
|
|
leaving a remainder of 1, throw an
|
|
<code><a href="common-dom-interfaces.html#invalid_character_err">INVALID_CHARACTER_ERR</a></code> exception and abort these
|
|
steps.</p>
|
|
|
|
</li><li>
|
|
|
|
<p>If <var title="">input</var> contains a character that is not
|
|
in the following list of characters and character ranges, throw an
|
|
<code><a href="common-dom-interfaces.html#invalid_character_err">INVALID_CHARACTER_ERR</a></code> exception and abort these
|
|
steps:</p>
|
|
|
|
<ul class="brief"><li>U+002B PLUS SIGN (+)
|
|
</li><li>U+002F SOLIDUS (/)
|
|
</li><li>U+0030 DIGIT ZERO (0) to U+0039 DIGIT NINE (9)
|
|
</li><li>U+0041 LATIN CAPITAL LETTER A to U+005A LATIN CAPITAL LETTER Z
|
|
</li><li>U+0061 LATIN SMALL LETTER A to U+007A LATIN SMALL LETTER Z
|
|
</li></ul></li>
|
|
|
|
<li><p>Let <var title="">output</var> be a string, initially
|
|
empty.</p></li>
|
|
|
|
<li><p>Let <var title="">buffer</var> be a buffer that can have
|
|
bits appended to it, initially empty.</p></li>
|
|
|
|
<li>
|
|
|
|
<p>While <var title="">position</var> does not point past the end
|
|
of <var title="">input</var>, run these substeps:</p>
|
|
|
|
<ol><li>
|
|
|
|
<p>Find the character pointed to by <var title="">position</var>
|
|
in the first column of the following table. Let <var title="">n</var> be the number given in the second cell of the
|
|
same row.</p>
|
|
|
|
<div id="base64-table">
|
|
<table><thead><tr><th>Character
|
|
</th><th>Number
|
|
</th></tr></thead><tbody><tr><td>A</td><td>0
|
|
</td></tr><tr><td>B</td><td>1
|
|
</td></tr><tr><td>C</td><td>2
|
|
</td></tr><tr><td>D</td><td>3
|
|
</td></tr><tr><td>E</td><td>4
|
|
</td></tr><tr><td>F</td><td>5
|
|
</td></tr><tr><td>G</td><td>6
|
|
</td></tr><tr><td>H</td><td>7
|
|
</td></tr><tr><td>I</td><td>8
|
|
</td></tr><tr><td>J</td><td>9
|
|
</td></tr><tr><td>K</td><td>10
|
|
</td></tr><tr><td>L</td><td>11
|
|
</td></tr><tr><td>M</td><td>12
|
|
</td></tr><tr><td>N</td><td>13
|
|
</td></tr><tr><td>O</td><td>14
|
|
</td></tr><tr><td>P</td><td>15
|
|
</td></tr><tr><td>Q</td><td>16
|
|
</td></tr><tr><td>R</td><td>17
|
|
</td></tr><tr><td>S</td><td>18
|
|
</td></tr><tr><td>T</td><td>19
|
|
</td></tr><tr><td>U</td><td>20
|
|
</td></tr><tr><td>V</td><td>21
|
|
</td></tr><tr><td>W</td><td>22
|
|
</td></tr><tr><td>X</td><td>23
|
|
</td></tr><tr><td>Y</td><td>24
|
|
</td></tr><tr><td>Z</td><td>25
|
|
</td></tr><tr><td>a</td><td>26
|
|
</td></tr><tr><td>b</td><td>27
|
|
</td></tr><tr><td>c</td><td>28
|
|
</td></tr><tr><td>d</td><td>29
|
|
</td></tr><tr><td>e</td><td>30
|
|
</td></tr><tr><td>f</td><td>31
|
|
</td></tr><tr><td>g</td><td>32
|
|
</td></tr><tr><td>h</td><td>33
|
|
</td></tr><tr><td>i</td><td>34
|
|
</td></tr><tr><td>j</td><td>35
|
|
</td></tr><tr><td>k</td><td>36
|
|
</td></tr><tr><td>l</td><td>37
|
|
</td></tr><tr><td>m</td><td>38
|
|
</td></tr><tr><td>n</td><td>39
|
|
</td></tr><tr><td>o</td><td>40
|
|
</td></tr><tr><td>p</td><td>41
|
|
</td></tr><tr><td>q</td><td>42
|
|
</td></tr><tr><td>r</td><td>43
|
|
</td></tr><tr><td>s</td><td>44
|
|
</td></tr><tr><td>t</td><td>45
|
|
</td></tr><tr><td>u</td><td>46
|
|
</td></tr><tr><td>v</td><td>47
|
|
</td></tr><tr><td>w</td><td>48
|
|
</td></tr><tr><td>x</td><td>49
|
|
</td></tr><tr><td>y</td><td>50
|
|
</td></tr><tr><td>z</td><td>51
|
|
</td></tr><tr><td>0</td><td>52
|
|
</td></tr><tr><td>1</td><td>53
|
|
</td></tr><tr><td>2</td><td>54
|
|
</td></tr><tr><td>3</td><td>55
|
|
</td></tr><tr><td>4</td><td>56
|
|
</td></tr><tr><td>5</td><td>57
|
|
</td></tr><tr><td>6</td><td>58
|
|
</td></tr><tr><td>7</td><td>59
|
|
</td></tr><tr><td>8</td><td>60
|
|
</td></tr><tr><td>9</td><td>61
|
|
</td></tr><tr><td>+</td><td>62
|
|
</td></tr><tr><td>/</td><td>63
|
|
</td></tr></tbody></table></div>
|
|
|
|
</li>
|
|
|
|
<li><p>Append to <var title="">buffer</var> the six bits
|
|
corresponding to <var title="">number</var>, most significant bit
|
|
first.</p></li>
|
|
|
|
<li><p>If <var title="">buffer</var> has accumulated 24 bits,
|
|
interpret them as three 8-bit big-endian numbers. Append the
|
|
three characters with code points equal to those numbers to <var title="">output</var>, in the same order, and then empty <var title="">buffer</var>.</p></li>
|
|
|
|
<li><p>Advance <var title="">position</var> by one
|
|
character.</p></li>
|
|
|
|
</ol></li>
|
|
|
|
<li>
|
|
|
|
<p>If <var title="">buffer</var> is not empty, it contains either
|
|
12 or 18 bits. If it contains 12 bits, discard the last four and
|
|
interpret the remaining eight as an 8-bit big-endian number. If it
|
|
contains 18 bits, discard the last two and interpret the remaining
|
|
16 as two 8-bit big-endian numbers. Append the one or two
|
|
characters with code points equal to those one or two numbers to
|
|
<var title="">output</var>, in the same order.</p>
|
|
|
|
<p class="note">The discarded bits mean that, for instance, <code title="">atob("YQ")</code> and <code title="">atob("YR")</code>
|
|
both return "<code title="">a</code>".</p>
|
|
|
|
</li>
|
|
|
|
<li><p>Return <var title="">output</var>.</p></li>
|
|
|
|
</ol></div><p class="note">Some base64 encoders add newlines or other
|
|
whitespace to their output. The <code title="dom-windowbase64-atob"><a href="#dom-windowbase64-atob">atob()</a></code> method throws an
|
|
exception if its input contains characters other than those
|
|
described by the regular expression bracket expression <code title="">[+/=0-9A-Za-z]</code>, so other characters need to be
|
|
removed before <code title="dom-windowbase64-atob"><a href="#dom-windowbase64-atob">atob()</a></code> is
|
|
used for decoding.</p></body></html>
|