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<!DOCTYPE html><html lang=en><head>
<meta content="text/html; charset=utf-8" http-equiv=Content-Type>
<title>CSS Animations Level 1</title>
<link href=../default.css rel=stylesheet type=text/css>
<link href=../csslogo.ico rel="shortcut icon" type=image/x-icon>
<style>
body {
background: url("https://www.w3.org/StyleSheets/TR/logo-ED") top left no-repeat white;
background-attachment: fixed;
color: black;
font-family: sans-serif;
margin: 0 auto;
max-width: 50em;
padding: 2em 1em 2em 70px;
}
:link { color: #00C; background: transparent }
:visited { color: #609; background: transparent }
a[href]:active { color: #C00; background: transparent }
a[href]:hover { background: #ffa }
a[href] img { border-style: none }
h1, h2, h3, h4, h5, h6 { text-align: left }
h1, h2, h3 { color: #005A9C; }
h1 { font: 170% sans-serif }
h2 { font: 140% sans-serif }
h3 { font: 120% sans-serif }
h4 { font: bold 100% sans-serif }
h5 { font: italic 100% sans-serif }
h6 { font: small-caps 100% sans-serif }
.hide { display: none }
div.head { margin-bottom: 1em }
div.head h1 { margin-top: 2em; clear: both }
div.head table { margin-left: 2em; margin-top: 2em }
p.copyright { font-size: small }
p.copyright small { font-size: small }
pre { margin-left: 2em }
dt { font-weight: bold }
ul.toc, ol.toc {
list-style: none;
}
</style>
<script defer src=//test.csswg.org/harness/annotate.js#css-animations-1_dev type=text/javascript></script>
</head>
<body class=h-entry>
<div class=head>
<p data-fill-with=logo><a class=logo href=http://www.w3.org/>
<img alt=W3C height=48 src=http://www.w3.org/Icons/w3c_home width=72>
</a>
</p>
<h1 class="p-name no-ref" id=title>CSS Animations Level 1</h1>
<h2 class="no-num no-toc no-ref heading settled heading" id=subtitle><span class=content>Editor’s Draft,
<span class=dt-updated><span class=value-title title=20140811>11 August 2014</span></span></span></h2>
<div data-fill-with=spec-metadata><dl><dt>This version:<dd><a class=u-url href=http://dev.w3.org/csswg/css3-animations/>http://dev.w3.org/csswg/css3-animations/</a><dt>Latest version:<dd><a href=http://www.w3.org/TR/css3-animations/>http://www.w3.org/TR/css3-animations/</a><dt>Editor’s Draft:<dd><a href=http://dev.w3.org/csswg/css3-animations/>http://dev.w3.org/csswg/css3-animations/</a><dt>Previous Versions:<dd><a href=http://www.w3.org/TR/2013/WD-css3-animations-20130219/ rel=previous>http://www.w3.org/TR/2013/WD-css3-animations-20130219/</a><dd><a href=http://www.w3.org/TR/2012/WD-css3-animations-20120403/ rel=previous>http://www.w3.org/TR/2012/WD-css3-animations-20120403/</a>
<dt>Feedback:</dt>
<dd><a href="mailto:www-style@w3.org?subject=%5Bcss-animations%5D%20feedback">www-style@w3.org</a>
with subject line
“<kbd>[css-animations] <var>… message topic …</var></kbd>”(<a href=http://lists.w3.org/Archives/Public/www-style/ rel=discussion>archives</a>)<dt>Test Suite:<dd><a href=http://test.csswg.org/suites/css-animations-1_dev/nightly-unstable/>http://test.csswg.org/suites/css-animations-1_dev/nightly-unstable/</a><dt>Editors:
<dd class="p-author h-card vcard"><a class="p-name fn u-email email" href=mailto:dino@apple.com>Dean Jackson</a> (<span class="p-org org">Apple Inc.</span>)<dd class="p-author h-card vcard"><a class="p-name fn u-email email" href=mailto:dbaron@dbaron.org>L. David Baron</a> (<span class="p-org org">Mozilla</span>)<dd class="p-author h-card vcard"><a class="p-name fn u-email email" href=mailto:galineau@adobe.com>Sylvain Galineau</a> (<span class="p-org org">Adobe</span>)<dt>Former Editors:
<dd class="p-author h-card vcard"><span class="p-name fn">David Hyatt</span> (<span class="p-org org">Apple Inc.</span>)<dd class="p-author h-card vcard"><span class="p-name fn">Chris Marrin</span> (<span class="p-org org">Apple Inc.</span>)<dt>Issues List:<dd><a href="https://www.w3.org/Bugs/Public/buglist.cgi?component=Animations&list_id=36653&product=CSS&query_format=advanced&resolution=---">In Bugzilla</a></dl></div>
<div data-fill-with=warning></div>
<p class=copyright data-fill-with=copyright><a href=http://www.w3.org/Consortium/Legal/ipr-notice#Copyright>Copyright</a> © 2014 <a href=http://www.w3.org/><abbr title="World Wide Web Consortium">W3C</abbr></a><sup>®</sup> (<a href=http://www.csail.mit.edu/><abbr title="Massachusetts Institute of Technology">MIT</abbr></a>, <a href=http://www.ercim.eu/><abbr title="European Research Consortium for Informatics and Mathematics">ERCIM</abbr></a>, <a href=http://www.keio.ac.jp/>Keio</a>, <a href=http://ev.buaa.edu.cn/>Beihang</a>), All Rights Reserved. W3C <a href=http://www.w3.org/Consortium/Legal/ipr-notice#Legal_Disclaimer>liability</a>, <a href=http://www.w3.org/Consortium/Legal/ipr-notice#W3C_Trademarks>trademark</a> and <a href=http://www.w3.org/Consortium/Legal/copyright-documents>document use</a> rules apply.
</p>
<hr title="Separator for header">
</div>
<h2 class="no-num no-toc no-ref heading settled heading" id=abstract><span class=content>Abstract</span></h2>
<p class=p-summary data-fill-with=abstract>This CSS module describes a way for authors to animate the values of CSS properties over time, using keyframes. The behavior of these keyframe animations can be controlled by specifying their duration, number of repeats, and repeating behavior.
<a href=http://www.w3.org/TR/CSS/>CSS</a> is a language for describing the rendering of structured documents
(such as HTML and XML)
on screen, on paper, in speech, etc.</p>
<h2 class="no-num no-toc no-ref heading settled heading" id=status><span class=content>Status of this document</span></h2>
<div data-fill-with=status><p>
This is a public copy of the editors’ draft.
It is provided for discussion only and may change at any moment.
Its publication here does not imply endorsement of its contents by W3C.
Don’t cite this document other than as work in progress.
<p>
The (<a href=http://lists.w3.org/Archives/Public/www-style/>archived</a>) public mailing list
<a href="mailto:www-style@w3.org?Subject=%5Bcss-animations%5D%20PUT%20SUBJECT%20HERE">www-style@w3.org</a>
(see <a href=http://www.w3.org/Mail/Request>instructions</a>)
is preferred for discussion of this specification.
When sending e-mail,
please put the text “css-animations” in the subject,
preferably like this:
“[css-animations] <em>…summary of comment…</em>”
<p>
This document was produced by the <a href=http://www.w3.org/Style/CSS/members>CSS Working Group</a>
(part of the <a href=http://www.w3.org/Style/>Style Activity</a>).
<p>
This document was produced by a group operating under
the <a href=http://www.w3.org/Consortium/Patent-Policy-20040205/>5 February 2004 W3C Patent Policy</a>.
W3C maintains a <a href=http://www.w3.org/2004/01/pp-impl/32061/status rel=disclosure>public list of any patent disclosures</a>
made in connection with the deliverables of the group;
that page also includes instructions for disclosing a patent.
An individual who has actual knowledge of a patent which the individual believes contains <a href=http://www.w3.org/Consortium/Patent-Policy-20040205/#def-essential>Essential Claim(s)</a>
must disclose the information in accordance with <a href=http://www.w3.org/Consortium/Patent-Policy-20040205/#sec-Disclosure>section 6 of the W3C Patent Policy</a>.</div>
<div data-fill-with=at-risk><p>The following features are at-risk, and may be dropped during the CR period:
<ul><li>the <code>pseudoElement</code> property of the <a class=css data-link-type=maybe href=#animationevent title=animationevent>AnimationEvent</a> interface</ul></div>
<h2 class="no-num no-toc no-ref heading settled heading" id=contents><span class=content>Table of Contents</span></h2>
<div data-fill-with=table-of-contents><ul class=toc>
<li><a href=#intro><span class=secno>1</span> Introduction</a>
<li><a href=#values><span class=secno>2</span> Values</a>
<li><a href=#animations><span class=secno>3</span> Animations</a>
<li><a href=#keyframes><span class=secno>4</span> Keyframes</a>
<ul class=toc>
<li><a href=#timing-functions><span class=secno>4.1</span> Timing functions for keyframes</a>
<li><a href=#animation-name><span class=secno>4.2</span> The <span class=property data-link-type=propdesc title=animation-name>animation-name</span> property</a>
<li><a href=#animation-duration><span class=secno>4.3</span> The <span class=property data-link-type=propdesc title=animation-duration>animation-duration</span> property</a>
<li><a href=#animation-timing-function><span class=secno>4.4</span> The <span class=property data-link-type=propdesc title=animation-timing-function>animation-timing-function</span> property</a>
<li><a href=#animation-iteration-count><span class=secno>4.5</span> The <span class=property data-link-type=propdesc title=animation-iteration-count>animation-iteration-count</span> property</a>
<li><a href=#animation-direction><span class=secno>4.6</span> The <span class=property data-link-type=propdesc title=animation-direction>animation-direction</span> property</a>
<li><a href=#animation-play-state><span class=secno>4.7</span> The <span class=property data-link-type=propdesc title=animation-play-state>animation-play-state</span> property</a>
<li><a href=#animation-delay><span class=secno>4.8</span> The <span class=property data-link-type=propdesc title=animation-delay>animation-delay</span> property</a>
<li><a href=#animation-fill-mode><span class=secno>4.9</span> The <span class=property data-link-type=propdesc title=animation-fill-mode>animation-fill-mode</span> property</a>
<li><a href=#animation><span class=secno>4.10</span> The <span class=property data-link-type=propdesc title=animation>animation</span> shorthand property</a></ul>
<li><a href=#events><span class=secno>5</span> Animation Events</a>
<ul class=toc>
<li><a href=#interface-animationevent><span class=secno>5.1</span> The <code>AnimationEvent</code> Interface</a>
<ul class=toc>
<li><a href=#interface-animationevent-idl><span class=secno>5.1.1</span> IDL Definition</a>
<li><a href=#interface-animationevent-attributes><span class=secno>5.1.2</span> Attributes</a></ul>
<li><a href=#event-animationevent><span class=secno>5.2</span> Types of <code>AnimationEvent</code></a></ul>
<li><a href=#interface-dom><span class=secno>6</span> DOM Interfaces</a>
<ul class=toc>
<li><a href=#interface-cssrule><span class=secno>6.1</span> The <code>CSSRule</code> Interface</a>
<ul class=toc>
<li><a href=#interface-cssrule-idl><span class=secno>6.1.1</span> IDL Definition</a></ul>
<li><a href=#interface-csskeyframerule><span class=secno>6.2</span> The <code>CSSKeyframeRule</code> Interface</a>
<ul class=toc>
<li><a href=#interface-csskeyframerule-idl><span class=secno>6.2.1</span> IDL Definition</a>
<li><a href=#interface-csskeyframerule-attributes><span class=secno>6.2.2</span> Attributes</a></ul>
<li><a href=#interface-csskeyframesrule><span class=secno>6.3</span> The <code>CSSKeyframesRule</code> Interface</a>
<ul class=toc>
<li><a href=#interface-csskeyframesrule-idl><span class=secno>6.3.1</span> IDL Definition</a>
<li><a href=#interface-csskeyframesrule-attributes><span class=secno>6.3.2</span> Attributes</a>
<li><a href=#interface-csskeyframesrule-appendrule><span class=secno>6.3.3</span> The <code>appendRule</code> method</a>
<li><a href=#interface-csskeyframesrule-deleterule><span class=secno>6.3.4</span> The <code>deleteRule</code> method</a>
<li><a href=#interface-csskeyframesrule-findrule><span class=secno>6.3.5</span> The <code>findRule</code> method</a></ul></ul>
<li><a href=#acknowledgements><span class=secno>7</span> Acknowledgements</a>
<li><a href=#wg-resolutions-pending><span class=secno>8</span> Working Group Resolutions that are pending editing</a>
<li><a href=#conformance><span class=secno></span> Conformance</a>
<ul class=toc>
<li><a href=#conventions><span class=secno></span> Document conventions</a>
<li><a href=#conformance-classes><span class=secno></span> Conformance classes</a>
<li><a href=#partial><span class=secno></span> Partial implementations</a>
<li><a href=#experimental><span class=secno></span> Experimental implementations</a>
<li><a href=#testing><span class=secno></span> Non-experimental implementations</a></ul>
<li><a href=#references><span class=secno></span> References</a>
<ul class=toc>
<li><a href=#normative><span class=secno></span> Normative References</a>
<li><a href=#informative><span class=secno></span> Informative References</a></ul>
<li><a href=#index><span class=secno></span> Index</a>
<li><a href=#property-index><span class=secno></span> Property index</a></ul></div>
<h2 class="heading settled heading" data-level=1 id=intro><span class=secno>1 </span><span class=content>
Introduction</span><a class=self-link href=#intro></a></h2>
<p> <em>This section is not normative</em>
<p> CSS Transitions <a data-biblio-type=informative data-link-type=biblio href=#css3-transitions title=css3-transitions>[CSS3-TRANSITIONS]</a> provide a way to interpolate
CSS property values when they change as a result of underlying
property changes. This provides an easy way to do simple animation,
but the start and end states of the animation are controlled by the
existing property values, and transitions provide little control to
the author on how the animation progresses.
<p> This proposal introduces defined animations, in which the author can
specify the changes in CSS properties over time as a set of keyframes.
Animations are similar to transitions in that they change the
presentational value of CSS properties over time. The principal difference
is that while transitions trigger implicitly when property values change,
animations are explicitly executed when the animation properties are applied.
Because of this, animations require explicit values for the properties
being animated. These values are specified using animation keyframes,
described below.
<p> Many aspects of the animation can be controlled, including how many times
the animation iterates, whether or not it alternates between the begin and
end values, and whether or not the animation should be running or paused.
An animation can also delay its start time.
<h2 class="heading settled heading" data-level=2 id=values><span class=secno>2 </span><span class=content>
Values</span><a class=self-link href=#values></a></h2>
<p> This specification follows the CSS property definition conventions
from <a data-biblio-type=normative data-link-type=biblio href=#css21 title=css21>[CSS21]</a>. Value types not defined in this specification are
defined in CSS Level 2 Revision 1 <a data-biblio-type=normative data-link-type=biblio href=#css21 title=css21>[CSS21]</a>. Other CSS modules may
expand the definitions of these value types: for example <a data-biblio-type=normative data-link-type=biblio href=#css3val title=css3val>[CSS3VAL]</a>,
when combined with this module, expands the definition of the
<a class="production css-code" data-link-type=type href=http://dev.w3.org/csswg/css-values-3/#length-value title="<length>"><length></a> value type as used in this specification.
<p> In addition to the property-specific values listed in their definitions,
all properties defined in this specification also accept the ‘initial’
and ‘inherit’ keyword as their property value. For readability it has
not been repeated explicitly.
<h2 class="heading settled heading" data-level=3 id=animations><span class=secno>3 </span><span class=content>
Animations</span><a class=self-link href=#animations></a></h2>
<p> CSS Animations affect computed property values. This effect happens by
adding a specified value to the CSS cascade (<a data-biblio-type=normative data-link-type=biblio href=#css3cascade title=css3cascade>[CSS3CASCADE]</a>) (at the
level for CSS Animations) that will produce the correct computed value
for the current state of the animation. As defined in <a data-biblio-type=normative data-link-type=biblio href=#css3cascade title=css3cascade>[CSS3CASCADE]</a>,
animations override all normal rules, but are overridden by !important
rules.
<p> If at one point in time there are multiple animations specifying behavior
for the same property, the animation which occurs last in the value
of <a class=property data-link-type=propdesc href=#propdef-animation-name title=animation-name>animation-name</a> will override the other animations at that point.
<p> An animation does not affect the computed value before the application of
the animation, before the animation delay has expired, and after the end of
the animation.
</p><figure>
<img alt="" src=./sandwich.png>
<figcaption>Computation of animated property values</figcaption>
</figure>
<p> The diagram above shows how property values are computed. The intrinsic
style is shown at the top of the diagram. The computed value is derived
from intrinsic style at the times when an animation is not running and
also when an animation is delayed (see below for specification of animation
delay). During an animation, the computed style is derived from the
animated value.
<p> The start time of an animation is the time at which the style applying
the animation and the corresponding @keyframes rule are both resolved.
If an animation is specified for an element but the corresponding
@keyframes rule does not yet exist, the animation cannot start; the
animation will start from the beginning as soon as a matching @keyframes
rule can be resolved. An animation specified by dynamically modifying the
element’s style will start when this style is resolved; that may be
immediately in the case of a pseudo style rule such as hover, or may be
when the scripting engine returns control to the browser (in the case of
style applied by script). Note that dynamically updating keyframe style
rules does not start or restart an animation.
<p> An animation applies to an element if its name appears as one of the
identifiers in the computed value of the <a class=property data-link-type=propdesc href=#propdef-animation-name title=animation-name>animation-name</a> property and the
animation uses a valid @keyframes rule. Once an
animation has started it continues until it ends or the <a class=property data-link-type=propdesc href=#propdef-animation-name title=animation-name>animation-name</a> is
removed. The values used for the keyframes and animation properties are
snapshotted at the time the animation starts. Changing them during the
execution of the animation has no effect. Note also that changing the value
of <a class=property data-link-type=propdesc href=#propdef-animation-name title=animation-name>animation-name</a> does not necessarily restart an animation (e.g., if a list
of animations are applied and one is removed from the list, only that animation
will stop; The other animations will continue). In order to restart an animation,
it must be removed then reapplied.
<p> The end of the animation is defined by the combination of the
<a class=property data-link-type=propdesc href=#propdef-animation-duration title=animation-duration>animation-duration</a>, <a class=property data-link-type=propdesc href=#propdef-animation-iteration-count title=animation-iteration-count>animation-iteration-count</a> and <a class=property data-link-type=propdesc href=#propdef-animation-fill-mode title=animation-fill-mode>animation-fill-mode</a>
properties.
<div class=example>
<pre>div {
animation-name: diagonal-slide;
animation-duration: 5s;
animation-iteration-count: 10;
}
@keyframes diagonal-slide {
from {
left: 0;
top: 0;
}
to {
left: 100px;
top: 100px;
}
}
</pre>
<p> This will produce an animation that moves an element from (0, 0) to
(100px, 100px) over five seconds and repeats itself nine times
(for a total of ten iterations).
</div>
<p> Setting the <a class=property data-link-type=propdesc href=http://dev.w3.org/csswg/css2/visuren.html#propdef-display title=display>display</a> property to <span class=css data-link-for=display data-link-type=maybe title=none>none</span> will terminate any running animation applied
to the element and its descendants. If an element has a <a class=property data-link-type=propdesc href=http://dev.w3.org/csswg/css2/visuren.html#propdef-display title=display>display</a> of <span class=css data-link-for=display data-link-type=maybe title=none>none</span>, updating
<a class=property data-link-type=propdesc href=http://dev.w3.org/csswg/css2/visuren.html#propdef-display title=display>display</a> to a value other than <span class=css data-link-for=display data-link-type=maybe title=none>none</span> will start all animations applied to the element
by the <a class=property data-link-type=propdesc href=#propdef-animation-name title=animation-name>animation-name</a> property, as well as all animations applied to descendants
with <a class=property data-link-type=propdesc href=http://dev.w3.org/csswg/css2/visuren.html#propdef-display title=display>display</a> other than <span class=css data-link-for=display data-link-type=maybe title=none>none</span>.
<p> While authors can use animations to create dynamically changing content, dynamically
changing content can lead to seizures in some users. For information on how to avoid
content that can lead to seizures, see Guideline 2.3: Seizures: Do not design content
in a way that is known to cause seizures (<a data-biblio-type=normative data-link-type=biblio href=#wcag20 title=wcag20>[WCAG20]</a>).
<p> Implementations may ignore animations when the rendering medium is not interactive e.g. when printed.
A future version of this specification may define how to render animations for these media.
<h2 class="heading settled heading" data-level=4 id=keyframes><span class=secno>4 </span><span class=content>
Keyframes</span><a class=self-link href=#keyframes></a></h2>
<p> Keyframes are used to specify the values for the animating properties at various points
during the animation. The keyframes specify the behavior of one cycle of the animation;
the animation may iterate one or more times.
<p> Keyframes are specified using a specialized CSS at-rule. A <dfn class=css-code data-dfn-type=at-rule data-export="" id=at-ruledef-keyframes>@keyframes<a class=self-link href=#at-ruledef-keyframes></a></dfn> rule consists of the
keyword "@keyframes", followed by an identifier giving a name for the animation (which will
be referenced using <a class=property data-link-type=propdesc href=#propdef-animation-name title=animation-name>animation-name</a>), followed by a set of style rules (delimited by curly
braces).
<p> The keyframe selector for a keyframe style rule consists of a comma-separated list of
percentage values or the keywords <span class=css data-link-type=maybe title=from>from</span> or <span class=css data-link-type=maybe title=to>to</span>. The selector is used to specify the
percentage along the duration of the animation that the keyframe represents. The keyframe
itself is specified by the block of property values declared on the selector. The keyword
<span class=css data-link-type=maybe title=from>from</span> is equivalent to the value <span class=css data-link-type=maybe title=0%>0%</span>. The keyword <span class=css data-link-type=maybe title=to>to</span> is equivalent to the value <span class=css data-link-type=maybe title=100%>100%</span>.
<span class=note>Note that the percentage unit specifier must be used on percentage values.
Therefore, <span class=css data-link-type=maybe title=0>0</span> is an invalid keyframe selector.</span>
<p> If a <span class=css data-link-type=maybe title=0%>0%</span> or <span class=css data-link-type=maybe title=from>from</span> keyframe is not specified, then the user agent constructs a <span class=css data-link-type=maybe title=0%>0%</span> keyframe
using the computed values of the properties being animated. If a <span class=css data-link-type=maybe title=100%>100%</span> or <span class=css data-link-type=maybe title=to>to</span> keyframe is not
specified, then the user agent constructs a <span class=css data-link-type=maybe title=100%>100%</span> keyframe using the computed values of the
properties being animated. If a keyframe selector specifies negative percentage values or values
higher than <span class=css data-link-type=maybe title=100%>100%</span>, then the keyframe will be ignored.
<p> The keyframe declaration block for a keyframe rule consists of properties and values. Properties
that are unable to be animated are ignored in these rules, with the exception of
<a class=property data-link-type=propdesc href=#propdef-animation-timing-function title=animation-timing-function>animation-timing-function</a>, the behavior of which is described below. In addition, keyframe rule
declarations qualified with !important are ignored.
<p> Issue: Need to describe what happens if a property is not present in all keyframes.
<p> The @keyframes rule that is used by an animation will be the last one encountered in sorted rules
order that matches the name of the animation specified by the <a class=property data-link-type=propdesc href=#propdef-animation-name title=animation-name>animation-name</a> property.
<div class=example>
<pre>div {
animation-name: slide-right;
animation-duration: 2s;
}
@keyframes slide-right {
from {
margin-left: 0px;
}
50% {
margin-left: 110px;
opacity: 1;
}
50% {
opacity: 0.9;
}
to {
margin-left: 200px;
}
}
</pre>
<p> At the 1s mark, the slide-right animation will have the same state as if we had defined the 50% rule like this:
<pre>
@keyframes slide-right {
50% {
margin-left: 110px;
opacity: 0.9;
}
to {
margin-left: 200px;
}
}
</pre>
</div>
<p class=note> Note: Since empty @keyframes rules are valid, they may hide the keyframes of those
preceding animation definitions with a matching name.
<p> To determine the set of keyframes, all of the values in the selectors are sorted in increasing order
by time. The rules within the @keyframes rule then cascade; the properties of a keyframe may thus derive
from more than one @keyframes rule with the same selector value.
<p> If a property is not specified for a keyframe, or is specified but invalid, the animation of that
property proceeds as if that keyframe did not exist. Conceptually, it is as if a set of keyframes is
constructed for each property that is present in any of the keyframes, and an animation is run
independently for each property.
<div class=example>
<pre>@keyframes wobble {
0% {
78B
left: 100px;
}
40% {
left: 150px;
}
60% {
left: 75px;
}
100% {
left: 100px;
}
}
</pre>
<p> Four keyframes are specified for the animation named "wobble". In the first keyframe,
shown at the beginning of the animation cycle, the value of the <a class=property data-link-type=propdesc href=http://dev.w3.org/csswg/css-position-3/#left title=left>left</a> property being
animated is <span class=css data-link-type=maybe title=100px>100px</span>. By 40% of the animation duration, <a class=property data-link-type=propdesc href=http://dev.w3.org/csswg/css-position-3/#left title=left>left</a> has animated to <span class=css data-link-type=maybe title=150px>150px</span>.
At 60% of the animation duration, <a class=property data-link-type=propdesc href=http://dev.w3.org/csswg/css-position-3/#left title=left>left</a> has animated back to <span class=css data-link-type=maybe title=75px>75px</span>. At the end of the
animation cycle, the value of <a class=property data-link-type=propdesc href=http://dev.w3.org/csswg/css-position-3/#left title=left>left</a> has returned to <span class=css data-link-type=maybe title=100px>100px</span>. The diagram below shows
the state of the animation if it were given a duration of <span class=css data-link-type=maybe title=10s>10s</span>.
</p><figure>
<img alt="" src=./animation1.png>
<figcaption>Animation states specified by keyframes</figcaption>
</figure>
</div>
<p> The following is the grammar for the keyframes rule:
<pre> keyframes_rule: KEYFRAMES_SYM S+ IDENT S* '{' S* keyframes_blocks '}' S*;
keyframes_blocks: [ keyframe_selector '{' S* declaration? [ ';' S* declaration? ]* '}' S* ]* ;
keyframe_selector: [ FROM_SYM | TO_SYM | PERCENTAGE ] S* [ ',' S* [ FROM_SYM | TO_SYM | PERCENTAGE ] S* ]*;
@{K}{E}{Y}{F}{R}{A}{M}{E}{S} {return KEYFRAMES_SYM;}
{F}{R}{O}{M} {return FROM_SYM;}
{T}{O} {return TO_SYM;}
</pre>
<h3 class="heading settled heading" data-level=4.1 id=timing-functions><span class=secno>4.1 </span><span class=content>
Timing functions for keyframes</span><a class=self-link href=#timing-functions></a></h3>
<p> A keyframe style rule may also declare the timing function that is to be used as the animation
moves to the next keyframe.
<div class=example>
<pre>@keyframes bounce {
from {
top: 100px;
animation-timing-function: ease-out;
}
25% {
top: 50px;
animation-timing-function: ease-in;
}
50% {
top: 100px;
animation-timing-function: ease-out;
}
75% {
top: 75px;
animation-timing-function: ease-in;
}
to {
top: 100px;
}
}
</pre>
<p> Five keyframes are specified for the animation named "bounce". Between the first and second
keyframe (i.e., between 0% and 25%) an ease-out timing function is used. Between the second
and third keyframe (i.e., between 25% and 50%) an ease-in timing function is used. And so on.
The effect will appear as an element that moves up the page 50px, slowing down as it reaches
its highest point then speeding up as it falls back to 100px. The second half of the animation
behaves in a similar manner, but only moves the element 25px up the page.
</div>
<p> A timing function specified on the <span class=css data-link-type=maybe title=to>to</span> or <span class=css data-link-type=maybe title=100%>100%</span> keyframe is ignored.
<p> See the <a class=property data-link-type=propdesc href=#propdef-animation-timing-function title=animation-timing-function>animation-timing-function</a> property for more information.
<h3 class="heading settled heading" data-level=4.2 id=animation-name><span class=secno>4.2 </span><span class=content>
The <a class=property data-link-type=propdesc href=#propdef-animation-name title=animation-name>animation-name</a> property</span><a class=self-link href=#animation-name></a></h3>
<p> The <a class=property data-link-type=propdesc href=#propdef-animation-name title=animation-name>animation-name</a> property defines a list of animations that apply. Each name is used to select
the keyframe at-rule that provides the property values for the animation. If the name does not match
any keyframe at-rule, there are no properties to be animated and the animation will not execute.
Furthermore, if the animation name is <code>none</code> then there will be no animation. This can be
used to override any animations coming from the cascade. If multiple animations are attempting to
modify the same property, then the animation closest to the end of the list of names wins.
<p> Each animation listed by name should have a corresponding value for the other animation properties
listed below. If the lists of values for the other animation properties do not have the same length,
the length of the <a class=property data-link-type=propdesc href=#propdef-animation-name title=animation-name>animation-name</a> list determines the number of items in each list examined when
starting animations. The lists are matched up from the first value: excess values at the end are not
used. If one of the other properties doesn’t have enough comma-separated values to match the number of
values of <a class=property data-link-type=propdesc href=#propdef-animation-name title=animation-name>animation-name</a>, the UA must calculate its used value by repeating the list of values until
there are enough. This truncation or repetition does not affect the computed value.
<p class=note> Note: This is analogous to the behavior of the ‘background-*’properties, with ‘background-image’ analogous
to <a class=property data-link-type=propdesc href=#propdef-animation-name title=animation-name>animation-name</a>.
<table class="definition propdef"><tr><th>Name:<td><dfn class=css-code data-dfn-type=property data-export="" id=propdef-animation-name>animation-name<a class=self-link href=#propdef-animation-name></a></dfn><tr><th>Value:<td class=prod><a class="production css-code" data-link-type=type href=#typedef-single-animation-name title="<single-animation-name>"><single-animation-name></a>#<tr><th>Initial:<td>none<tr><th>Applies to:<td>all elements, ::before and ::after pseudo-elements<tr><th>Inherited:<td>none<tr><th>Media:<td>visual<tr><th>Computed value:<td>As specified<tr><th>Canonical order:<td>per grammar<tr><th>Percentages:<td>N/A<tr><th>Animatable:<td>no</table>
<p> <dfn class=css-code data-dfn-type=type data-export="" id=typedef-single-animation-name><single-animation-name><a class=self-link href=#typedef-single-animation-name></a></dfn> = none | <a class="production css-code" data-link-type=type href=http://dev.w3.org/csswg/css-values-3/#identifier-value title="<custom-ident>"><custom-ident></a>
<p> The values of <a class=property data-link-type=propdesc href=#propdef-animation-name title=animation-name>animation-name</a> have the following meanings:
<dl data-dfn-for=animation-name data-dfn-type=value>
<dt><dfn class=css-code data-dfn-for=animation-name data-dfn-type=value data-export="" id=valuedef-none0>none<a class=self-link href=#valuedef-none0></a></dfn>
<dd>
No keyframes are specified at all, so there will be no animation.
Any other animations properties specified for this animation have no effect.
<dt><dfn class=css-code data-dfn-for=animation-name data-dfn-type=value data-export="" id=valuedef-custom-ident><a class="production css-code" data-link-type=type href=http://dev.w3.org/csswg/css-values-3/#identifier-value title="<custom-ident>"><custom-ident></a><a class=self-link href=#valuedef-custom-ident></a></dfn>
<dd>
The animation will use the keyframes with the name specified by the <a class="production css-code" data-link-type=type href=http://dev.w3.org/csswg/css-values-3/#identifier-value title="<custom-ident>"><custom-ident></a>,
if they exist.
If no such keyframes exist,
there is no animation.
</dl>
<h3 class="heading settled heading" data-level=4.3 id=animation-duration><span class=secno>4.3 </span><span class=content>
The <a class=property data-link-type=propdesc href=#propdef-animation-duration title=animation-duration>animation-duration</a> property</span><a class=self-link href=#animation-duration></a></h3>
<p> The <a class=property data-link-type=propdesc href=#propdef-animation-duration title=animation-duration>animation-duration</a> property defines duration of a single animation cycle.
<table class="definition propdef"><tr><th>Name:<td><dfn class=css-code data-dfn-type=property data-export="" id=propdef-animation-duration>animation-duration<a class=self-link href=#propdef-animation-duration></a></dfn><tr><th>Value:<td class=prod><a class="production css-code" data-link-type=type href=http://dev.w3.org/csswg/css-values-3/#time-value title="<time>"><time></a>#<tr><th>Initial:<td>0s<tr><th>Applies to:<td>all elements, ::before and ::after pseudo-elements<tr><th>Inherited:<td>no<tr><th>Media:<td>visual<tr><th>Computed value:<td>As specified<tr><th>Canonical order:<td>per grammar<tr><th>Percentages:<td>N/A<tr><th>Animatable:<td>no</table>
<dl>
<dt><dfn class=css-code data-dfn-for=animation-duration data-dfn-type=value data-export="" id=valuedef-time0><a class="production css-code" data-link-type=type href=http://dev.w3.org/csswg/css-values-3/#time-value title="<time>"><time></a><a class=self-link href=#valuedef-time0></a></dfn>
<dd>
The <a class="production css-code" data-link-type=type href=http://dev.w3.org/csswg/css-values-3/#time-value title="<time>"><time></a> specifies the length of time that an animation takes to complete one cycle.
A negative <a class="production css-code" data-link-type=type href=http://dev.w3.org/csswg/css-values-3/#time-value title="<time>"><time></a> is invalid.
<p> If the <a class="production css-code" data-link-type=type href=http://dev.w3.org/csswg/css-values-3/#time-value title="<time>"><time></a> is <span class=css data-link-type=maybe title=0s>0s</span>, like the initial value,
the keyframes of the animation have no effect,
but the animation itself still occurs instantaneously.
That is, <a class=property data-link-type=propdesc href=#propdef-animation-fill-mode title=animation-fill-mode>animation-fill-mode</a> applies as normal,
filling backwards or forwards as appropriate,
and animation events still fire.
</dl>
<h3 class="heading settled heading" data-level=4.4 id=animation-timing-function><span class=secno>4.4 </span><span class=content>
The <a class=property data-link-type=propdesc href=#propdef-animation-timing-function title=animation-timing-function>animation-timing-function</a> property</span><a class=self-link href=#animation-timing-function></a></h3>
<p> The <a class=property data-link-type=propdesc href=#propdef-animation-timing-function title=animation-timing-function>animation-timing-function</a> property describes how the animation will progress over
one cycle of its duration. See the <a class=property data-link-type=propdesc href=http://dev.w3.org/csswg/css-transitions-1/#transition-timing-function title=transition-timing-function>transition-timing-function</a> property <a data-biblio-type=normative data-link-type=biblio href=#css3-transitions title=css3-transitions>[CSS3-TRANSITIONS]</a>
for a complete description of timing function calculation.
<table class="definition propdef"><tr><th>Name:<td><dfn class=css-code data-dfn-type=property data-export="" id=propdef-animation-timing-function>animation-timing-function<a class=self-link href=#propdef-animation-timing-function></a></dfn><tr><th>Value:<td class=prod><a class="production css-code" data-link-type=type href=#typedef-single-timing-function title="<single-timing-function>"><single-timing-function></a>#<tr><th>Initial:<td>ease<tr><th>Applies to:<td>all elements, ::before and ::after pseudo-elements<tr><th>Inherited:<td>no<tr><th>Media:<td>visual<tr><th>Computed value:<td>As specified<tr><th>Canonical order:<td>per grammar<tr><th>Percentages:<td>N/A<tr><th>Animatable:<td>no</table>
<p> The values and meaning of <dfn class=css-code data-dfn-type=type data-export="" id=typedef-single-timing-function><single-timing-function><a class=self-link href=#typedef-single-timing-function></a></dfn>
are identical to those of <a class="production css-code" data-link-type=type href=http://dev.w3.org/csswg/css-transitions-1/#single-transition-timing-function title="<single-transition-timing-function>"><single-transition-timing-function></a> <a data-biblio-type=normative data-link-type=biblio href=#css3-transitions title=css3-transitions>[CSS3-TRANSITIONS]</a>.
<p> The timing function specified applies to each iteration of the animation,
not the entire animation in full.
For example, if an animation has <a class=css data-link-type=propdesc href=#propdef-animation-timing-function title=animation-timing-function>animation-timing-function: ease-in-out; animation-iteration-count: 2;</a>,
it will ease in at the start,
ease out as it approaches the end of its first iteration,
ease in at the start of its second iteration,
and ease out again as it approaches the end of the animation.
<p class=note> Note: Unlike other animation properties,
<a class=property data-link-type=propdesc href=#propdef-animation-timing-function title=animation-timing-function>animation-timing-function</a> has an effect when specified on an individual keyframe.
See <a href=#timing-functions section=""></a> for more detail on this.
<h3 class="heading settled heading" data-level=4.5 id=animation-iteration-count><span class=secno>4.5 </span><span class=content>
The <a class=property data-link-type=propdesc href=#propdef-animation-iteration-count title=animation-iteration-count>animation-iteration-count</a> property</span><a class=self-link href=#animation-iteration-count></a></h3>
<p> The <a class=property data-link-type=propdesc href=#propdef-animation-iteration-count title=animation-iteration-count>animation-iteration-count</a> property specifies the number of times an animation cycle
is played. The initial value is <span class=css data-link-type=maybe title=1>1</span>, meaning the animation will play from beginning to end
once. This property is often used in conjunction with an
<a class=property data-link-type=propdesc href=#propdef-animation-direction title=animation-direction>animation-direction</a> value of <a class=css data-link-type=maybe href=#valuedef-alternate title=alternate>alternate</a>, which will cause the animation to play in
reverse on alternate cycles.
<table class="definition propdef"><tr><th>Name:<td><dfn class=css-code data-dfn-type=property data-export="" id=propdef-animation-iteration-count>animation-iteration-count<a class=self-link href=#propdef-animation-iteration-count></a></dfn><tr><th>Value:<td class=prod><a class="production css-code" data-link-type=type href=#typedef-single-animation-iteration-count title="<single-animation-iteration-count>"><single-animation-iteration-count></a>#<tr><th>Initial:<td>1<tr><th>Applies to:<td>all elements, ::before and ::after pseudo-elements<tr><th>Inherited:<td>no<tr><th>Media:<td>visual<tr><th>Computed value:<td>As specified<tr><th>Canonical order:<td>per grammar<tr><th>Percentages:<td>N/A<tr><th>Animatable:<td>no</table>
<p> <dfn class=css-code data-dfn-type=type data-export="" id=typedef-single-animation-iteration-count><single-animation-iteration-count><a class=self-link href=#typedef-single-animation-iteration-count></a></dfn> = infinite | <a class="production css-code" data-link-type=type href=http://dev.w3.org/csswg/css-values-3/#number-value title="<number>"><number></a>
<dl data-dfn-for=animation-iteration-count data-dfn-type=value>
<dt><dfn class=css-code data-dfn-for=animation-iteration-count data-dfn-type=value data-export="" id=valuedef-infinite>infinite<a class=self-link href=#valuedef-infinite></a></dfn>
<dd>
The animation will repeat forever.
<dt><dfn class=css-code data-dfn-for=animation-iteration-count data-dfn-type=value data-export="" id=valuedef-number><a class="production css-code" data-link-type=type href=http://dev.w3.org/csswg/css-values-3/#number-value title="<number>"><number></a><a class=self-link href=#valuedef-number></a></dfn>
<dd>
The animation will repeat the specified number of times.
If the number is not an integer,
the animation will end partway through its last cycle.
Negative numbers are invalid.
<p> A value of <span class=css data-link-type=maybe title=0>0</span> is valid and,
similar to an <a class=property data-link-type=propdesc href=#propdef-animation-duration title=animation-duration>animation-duration</a> of <span class=css data-link-type=maybe title=0s>0s</span>,
causes the animation to occur instantaneously.
</dl>
<h3 class="heading settled heading" data-level=4.6 id=animation-direction><span class=secno>4.6 </span><span class=content>
The <a class=property data-link-type=propdesc href=#propdef-animation-direction title=animation-direction>animation-direction</a> property</span><a class=self-link href=#animation-direction></a></h3>
<p> The <a class=property data-link-type=propdesc href=#propdef-animation-direction title=animation-direction>animation-direction</a> property defines whether or not the animation should play in reverse
on some or all cycles. When an animation is played in reverse the timing functions are also
reversed. For example, when played in reverse an <span class=css data-link-type=maybe title=ease-in>ease-in</span> animation would appear to be an
<span class=css data-link-type=maybe title=ease-out>ease-out</span> animation.
<table class="definition propdef"><tr><th>Name:<td><dfn class=css-code data-dfn-type=property data-export="" id=propdef-animation-direction>animation-direction<a class=self-link href=#propdef-animation-direction></a></dfn><tr><th>Value:<td class=prod><a class="production css-code" data-link-type=type href=#typedef-single-animation-direction title="<single-animation-direction>"><single-animation-direction></a>#<tr><th>Initial:<td>normal<tr><th>Applies to:<td>all elements, ::before and ::after pseudo-elements<tr><th>Inherited:<td>no<tr><th>Media:<td>visual<t
8821
r><th>Computed value:<td>As specified<tr><th>Canonical order:<td>per grammar<tr><th>Percentages:<td>N/A<tr><th>Animatable:<td>no</table>
<p> <dfn class=css-code data-dfn-type=type data-export="" id=typedef-single-animation-direction><single-animation-direction><a class=self-link href=#typedef-single-animation-direction></a></dfn> = normal | reverse | alternate | alternate-reverse
<dl data-dfn-for=animation-direction data-dfn-type=value>
<dt><dfn class=css-code data-dfn-for=animation-direction data-dfn-type=value data-export="" id=valuedef-normal>normal<a class=self-link href=#valuedef-normal></a></dfn>
<dd>
All iterations of the animation are played as specified.
<dt><dfn class=css-code data-dfn-for=animation-direction data-dfn-type=value data-export="" id=valuedef-reverse>reverse<a class=self-link href=#valuedef-reverse></a></dfn>
<dd>
All iterations of the animation are played in the reverse direction
from the way they were specified.
<dt><dfn class=css-code data-dfn-for=animation-direction data-dfn-type=value data-export="" id=valuedef-alternate>alternate<a class=self-link href=#valuedef-alternate></a></dfn>
<dd>
The animation cycle iterations that are odd counts are played in the
normal direction, and the animation cycle iterations that are even
counts are played in a reverse direction.
<dt><dfn class=css-code data-dfn-for=animation-direction data-dfn-type=value data-export="" id=valuedef-alternate-reverse>alternate-reverse<a class=self-link href=#valuedef-alternate-reverse></a></dfn>
<dd>
The animation cycle iterations that are odd counts are played in the
reverse direction, and the animation cycle iterations that are even
counts are played in a normal direction.
</dl>
<p class=note> Note: For the purpose of determining whether an iteration is even or odd,
iterations start counting from 1.
<h3 class="heading settled heading" data-level=4.7 id=animation-play-state><span class=secno>4.7 </span><span class=content>
The <a class=property data-link-type=propdesc href=#propdef-animation-play-state title=animation-play-state>animation-play-state</a> property</span><a class=self-link href=#animation-play-state></a></h3>
<p> The <a class=property data-link-type=propdesc href=#propdef-animation-play-state title=animation-play-state>animation-play-state</a> property defines whether the animation is running or paused.
<table class="definition propdef"><tr><th>Name:<td><dfn class=css-code data-dfn-type=property data-export="" id=propdef-animation-play-state>animation-play-state<a class=self-link href=#propdef-animation-play-state></a></dfn><tr><th>Value:<td class=prod><a class="production css-code" data-link-type=type href=#typedef-single-animation-play-state title="<single-animation-play-state>"><single-animation-play-state></a>#<tr><th>Initial:<td>running<tr><th>Applies to:<td>all elements, ::before and ::after pseudo-elements<tr><th>Inherited:<td>no<tr><th>Media:<td>visual<tr><th>Computed value:<td>As specified<tr><th>Canonical order:<td>per grammar<tr><th>Percentages:<td>N/A<tr><th>Animatable:<td>no</table>
<p> <dfn class=css-code data-dfn-type=type data-export="" id=typedef-single-animation-play-state><single-animation-play-state><a class=self-link href=#typedef-single-animation-play-state></a></dfn> = running | paused
<dl data-dfn-for=animation-play-state data-dfn-type=value>
<dt><dfn class=css-code data-dfn-for=animation-play-state data-dfn-type=value data-export="" id=valuedef-running>running<a class=self-link href=#valuedef-running></a></dfn>
<dd>
While this property is set to <a class=css data-link-type=maybe href=#valuedef-running title=running>running</a>,
the animation proceeds as normal.
<dt><dfn class=css-code data-dfn-for=animation-play-state data-dfn-type=value data-export="" id=valuedef-paused>paused<a class=self-link href=#valuedef-paused></a></dfn>
<dd>
While this property is set to <a class=css data-link-type=maybe href=#valuedef-paused title=paused>paused</a>,
the animation is paused.
The animation continues to apply to the element with the progress it had made before being paused.
When unpaused (set back to <a class=css data-link-type=maybe href=#valuedef-running title=running>running</a>), it restarts from where it left off,
as if the "clock" that controls the animation had stopped and started again.
<p> If the property is set to <a class=css data-link-type=maybe href=#valuedef-paused title=paused>paused</a> during the delay phase of the animation,
the delay clock is also paused and resumes as soon as <a class=property data-link-type=propdesc href=#propdef-animation-play-state title=animation-play-state>animation-play-state</a> is set back to <a class=css data-link-type=maybe href=#valuedef-running title=running>running</a>.
</dl>
<h3 class="heading settled heading" data-level=4.8 id=animation-delay><span class=secno>4.8 </span><span class=content>
The <a class=property data-link-type=propdesc href=#propdef-animation-delay title=animation-delay>animation-delay</a> property</span><a class=self-link href=#animation-delay></a></h3>
<p> The <a class=property data-link-type=propdesc href=#propdef-animation-delay title=animation-delay>animation-delay</a> property defines when the animation will start. It allows an animation
to begin execution some time after it is applied,
or to appear to have begun execution some time <em>before</em> it is applied.
<table class="definition propdef"><tr><th>Name:<td><dfn class=css-code data-dfn-type=property data-export="" id=propdef-animation-delay>animation-delay<a class=self-link href=#propdef-animation-delay></a></dfn><tr><th>Value:<td class=prod><a class="production css-code" data-link-type=type href=http://dev.w3.org/csswg/css-values-3/#time-value title="<time>"><time></a>#<tr><th>Initial:<td>0s<tr><th>Applies to:<td>all elements, ::before and ::after pseudo-elements<tr><th>Inherited:<td>no<tr><th>Media:<td>visual<tr><th>Computed value:<td>As specified<tr><th>Canonical order:<td>per grammar<tr><th>Percentages:<td>N/A<tr><th>Animatable:<td>no</table>
<dl>
<dt><dfn class=css-code data-dfn-for=animation-delay data-dfn-type=value data-export="" id=valuedef-time><a class="production css-code" data-link-type=type href=http://dev.w3.org/csswg/css-values-3/#time-value title="<time>"><time></a><a class=self-link href=#valuedef-time></a></dfn>
<dd>
The <a class="production css-code" data-link-type=type href=http://dev.w3.org/csswg/css-values-3/#time-value title="<time>"><time></a> defines how long of a delay there is between the start of the animation
(when the animation is applied to the element via these properties)
and when it begins executing.
A delay of <span class=css data-link-type=maybe title=0s>0s</span> (the initial value) means that the animation will execute as soon as it is applied.
<p> A negative delay is <strong>valid</strong>.
Similar to a delay of <span class=css data-link-type=maybe title=0s>0s</span>, it means that the animation executes immediately,
but is automatically progressed by the absolute value of the delay,
as if the animation had started the specified time in the past,
and so it appears to start partway through its play-cycle already.
If an animation’s keyframes have an implied starting value,
the values are taken from the time the animation starts,
not some time in the past.
</dl>
<h3 class="heading settled heading" data-level=4.9 id=animation-fill-mode><span class=secno>4.9 </span><span class=content>
The <a class=property data-link-type=propdesc href=#propdef-animation-fill-mode title=animation-fill-mode>animation-fill-mode</a> property</span><a class=self-link href=#animation-fill-mode></a></h3>
<p> The <a class=property data-link-type=propdesc href=#propdef-animation-fill-mode title=animation-fill-mode>animation-fill-mode</a> property defines what values are applied by the animation
outside the time it is executing. By default, an animation will not affect property
values between the time it is applied (the ‘animation-name’ property is set on an
element) and the time it begins execution (which is determined by the <a class=property data-link-type=propdesc href=#propdef-animation-delay title=animation-delay>animation-delay</a>
property). Also, by default an animation does not affect property values after the
animation ends (determined by the <a class=property data-link-type=propdesc href=#propdef-animation-duration title=animation-duration>animation-duration</a> and <a class=property data-link-type=propdesc href=#propdef-animation-iteration-count title=animation-iteration-count>animation-iteration-count</a> properties).
The <a class=property data-link-type=propdesc href=#propdef-animation-fill-mode title=animation-fill-mode>animation-fill-mode</a> property can override this behavior.
<table class="definition propdef"><tr><th>Name:<td><dfn class=css-code data-dfn-type=property data-export="" id=propdef-animation-fill-mode>animation-fill-mode<a class=self-link href=#propdef-animation-fill-mode></a></dfn><tr><th>Value:<td class=prod><a class="production css-code" data-link-type=type href=#typedef-single-animation-fill-mode title="<single-animation-fill-mode>"><single-animation-fill-mode></a>#<tr><th>Initial:<td>none<tr><th>Applies to:<td>all elements, ::before and ::after pseudo-elements<tr><th>Inherited:<td>no<tr><th>Media:<td>visual<tr><th>Computed value:<td>As specified<tr><th>Canonical order:<td>per grammar<tr><th>Percentages:<td>N/A<tr><th>Animatable:<td>no</table>
<p> <dfn class=css-code data-dfn-type=type data-export="" id=typedef-single-animation-fill-mode><single-animation-fill-mode><a class=self-link href=#typedef-single-animation-fill-mode></a></dfn> = none | forwards | backwards | both
<dl data-dfn-for=animation-fill-mode data-dfn-type=value>
<dt><dfn class=css-code data-dfn-for=animation-fill-mode data-dfn-type=value data-export="" id=valuedef-none>none<a class=self-link href=#valuedef-none></a></dfn>
<dd>
The animation has no effect when it is applied but not executing.
<dt><dfn class=css-code data-dfn-for=animation-fill-mode data-dfn-type=value data-export="" id=valuedef-forwards>forwards<a class=self-link href=#valuedef-forwards></a></dfn>
<dd>
After the animation is done executing
(has played the number of times specified by its <a class=property data-link-type=propdesc href=#propdef-animation-iteration-count title=animation-iteration-count>animation-iteration-count</a> value)
it continues to apply the values that it ended its last complete iteration with.
This will be the values specified or implied for either its <span class=css data-link-type=maybe title=100%>100%</span> or <span class=css data-link-type=maybe title=0%>0%</span> keyframe,
depending on the direction that the last complete iteration was executing in
(per <a class=property data-link-type=propdesc href=#propdef-animation-direction title=animation-direction>animation-direction</a>).
If the animation didn’t complete an entire iteration
(if the iteration count was <span class=css data-link-type=maybe title=0>0</span> or a value less than 1)
the values specified or implied for its <span class=css data-link-type=maybe title=0%>0%</span> keyframe are used.
<p class=note> Note: If <a class=property data-link-type=propdesc href=#propdef-animation-iteration-count title=animation-iteration-count>animation-iteration-count</a> is a non-integer value,
the animation will stop executing partway through its animation cycle,
but a forwards fill will still apply the values of the <span class=css data-link-type=maybe title=100%>100%</span> keyframe,
not whatever values were being applied at the time the animation stopped executing.
<p> Issue: Why does it ignore the progress made by a non-integer iteration count?
<p> Issue: What happens with <a class=css data-link-type=propdesc href=#propdef-animation-duration title=animation-duration>animation-duration: 0; animation-iteration-count: infinite;</a>?
The animation is instantaneous,
but there is no "last complete iteration".
In particular, you can’t tell whether to use the 0% or 100% keyframe.
<dt><dfn class=css-code data-dfn-for=animation-fill-mode data-dfn-type=value data-export="" id=valuedef-backwards>backwards<a class=self-link href=#valuedef-backwards></a></dfn>
<dd>
Before the animation has begun executing
(during the period specified by <a class=property data-link-type=propdesc href=#propdef-animation-delay title=animation-delay>animation-delay</a>),
the animation applies the values that it will start the first iteration with.
If the <a class=property data-link-type=propdesc href=#propdef-animation-direction title=animation-direction>animation-direction</a> is <a class=css data-link-type=maybe href=#valuedef-normal title=normal>normal</a> or <a class=css data-link-type=maybe href=#valuedef-alternate title=alternate>alternate</a>,
the values specified or implied for its <span class=css data-link-type=maybe title=0%>0%</span> keyframe are used;
if the <a class=property data-link-type=propdesc href=#propdef-animation-direction title=animation-direction>animation-direction</a> is <a class=css data-link-type=maybe href=#valuedef-reverse title=reverse>reverse</a> or <a class=css data-link-type=maybe href=#valuedef-alternate-reverse title=alternate-reverse>alternate-reverse</a>,
the values specified or implied for its <span class=css data-link-type=maybe title=100%>100%</span> keyframe are used.
<dt><dfn class=css-code data-dfn-for=animation-fill-mode data-dfn-type=value data-export="" id=valuedef-both>both<a class=self-link href=#valuedef-both></a></dfn>
<dd>
The effects of both <a class=css data-link-type=maybe href=#valuedef-forwards title=forwards>forwards</a> and <a class=css data-link-type=maybe href=#valuedef-backwards title=backwards>backwards</a> fill apply.
</dl>
<h3 class="heading settled heading" data-level=4.10 id=animation><span class=secno>4.10 </span><span class=content>
The <a class=property data-link-type=propdesc href=#propdef-animation title=animation>animation</a> shorthand property</span><a class=self-link href=#animation></a></h3>
<p> The <a class=property data-link-type=propdesc href=#propdef-animation title=animation>animation</a> shorthand property is a comma-separated list of animation definitions. Each item in
the list gives one item of the value for all of the subproperties of the shorthand, which are known
as the animation properties. (See the definition of <a class=property data-link-type=propdesc href=#propdef-animation-name title=animation-name>animation-name</a> for what happens when these
properties have lists of different lengths, a problem that cannot occur when they are defined using
only the <a class=property data-link-type=propdesc href=#propdef-animation title=animation>animation</a> shorthand.)
<table class="definition propdef"><tr><th>Name:<td><dfn class=css-code data-dfn-type=property data-export="" id=propdef-animation>animation<a class=self-link href=#propdef-animation></a></dfn><tr><th>Value:<td class=prod><a class="production css-code" data-link-type=type href=#typedef-single-animation title="<single-animation>"><single-animation></a>#<tr><th>Initial:<td>see individual properties<tr><th>Applies to:<td>all elements, ::before and ::after pseudo-elements<tr><th>Inherited:<td>no<tr><th>Media:<td>visual<tr><th>Computed value:<td>As specified<tr><th>Canonical order:<td>per grammar<tr><th>Percentages:<td>N/A<tr><th>Animatable:<td>no</table>
<p> <dfn class=css-code data-dfn-type=type data-export="" id=typedef-single-animation><single-animation><a class=self-link href=#typedef-single-animation></a></dfn> = <a class="production css-code" data-link-type=type href=http://dev.w3.org/csswg/css-values-3/#time-value title="<time>"><time></a> || <a class="production css-code" data-link-type=type href=#typedef-single-timing-function title="<single-timing-function>"><single-timing-function></a> || <a class="production css-code" data-link-type=type href=http://dev.w3.org/csswg/css-values-3/#time-value title="<time>"><time></a> || <a class="production css-code" data-link-type=type href=#typedef-single-animation-iteration-count title="<single-animation-iteration-count>"><single-animation-iteration-count></a> || <a class="production css-code" data-link-type=type href=#typedef-single-animation-direction title="<single-animation-direction>"><single-animation-direction></a> || <a class="production css-code" data-link-type=type href=#typedef-single-animation-fill-mode title="<single-animation-fill-mode>"><single-animation-fill-mode></a> || <a class="production css-code" data-link-type=type href=#typedef-single-animation-play-state title="<single-animation-play-state>"><single-animation-play-state></a> || <a class="production css-code" data-link-type=type href=#typedef-single-animation-name title="<single-animation-name>"><single-animation-name></a>
<p> Note that order is important within each animation definition: the first value in each
<a class="production css-code" data-link-type=type href=#typedef-single-animation title="<single-animation>"><single-animation></a> that can be parsed as a <a class="production css-code" data-link-type=type href=http://dev.w3.org/csswg/css-values-3/#time-value title="<time>"><time></a> is assigned to the <a class=property data-link-type=propdesc href=#propdef-animation-duration title=animation-duration>animation-duration</a>,
and the second value in each <a class="production css-code" data-link-type=type href=#typedef-single-animation title="<single-animation>"><single-animation></a> that can be parsed as a <a class="production css-code" data-link-type=type href=http://dev.w3.org/csswg/css-values-3/#time-value title="<time>"><time></a> is assigned to
<a class=property data-link-type=propdesc href=#propdef-animation-delay title=animation-delay>animation-delay</a>.
<p> Note that order is also important within each animation definition for distinguishing
<a class="production css-code" data-link-type=type href=#typedef-single-animation-name title="<single-animation-name>"><single-animation-name></a> values from other keywords. When parsing, keywords that are valid for
properties other than <a class=property data-link-type=propdesc href=#propdef-animation-name title=animation-name>animation-name</a>
whose values were not found earlier in the shorthand
must be accepted for those properties rather than for
<a class=property data-link-type=propdesc href=#propdef-animation-name title=animation-name>animation-name</a>. Furthermore, when serializing, default values of other properties must be
output in at least the cases necessary to distinguish an <a class=property data-link-type=propdesc href=#propdef-animation-name title=animation-name>animation-name</a> that could
be a value of another property, and may be output in additional cases.
<div class=example>
For example, a value parsed from <a class=css data-link-type=propdesc href=#propdef-animation title=animation>animation: 3s none backwards</a>
(where <a class=property data-link-type=propdesc href=#propdef-animation-fill-mode title=animation-fill-mode>animation-fill-mode</a> is <a class=css data-link-for=animation-fill-mode data-link-type=maybe href=#valuedef-none title=none>none</a>
and <a class=property data-link-type=propdesc href=#propdef-animation-name title=animation-name>animation-name</a> is <span class=css data-link-for=animation-name data-link-type=maybe title=backwards>backwards</span>)
must not be serialized as <a class=css data-link-type=propdesc href=#propdef-animation title=animation>animation: 3s backwards</a>
(where <a class=property data-link-type=propdesc href=#propdef-animation-fill-mode title=animation-fill-mode>animation-fill-mode</a> is <a class=css data-link-for=animation-fill-mode data-link-type=maybe href=#valuedef-backwards title=backwards>backwards</a>
and <a class=property data-link-type=propdesc href=#propdef-animation-name title=animation-name>animation-name</a> is <a class=css data-link-for=animation-name data-link-type=maybe href=#valuedef-none0 title=none>none</a>).
</div>
<h2 class="heading settled heading" data-level=5 id=events><span class=secno>5 </span><span class=content>
Animation Events</span><a class=self-link href=#events></a></h2>
<p> Several animation-related events are available through the DOM Event system. The start and
end of an animation, and the end of each iteration of an animation, all generate DOM events.
An element can have multiple properties being animated simultaneously. This can occur either
with a single <a class=property data-link-type=propdesc href=#propdef-animation-name title=animation-name>animation-name</a> value with keyframes containing multiple properties, or with
multiple <a class=property data-link-type=propdesc href=#propdef-animation-name title=animation-name>animation-name</a> values. For the purposes of events, each <a class=property data-link-type=propdesc href=#propdef-animation-name title=animation-name>animation-name</a> specifies
a single animation. Therefore an event will be generated for each <a class=property data-link-type=propdesc href=#propdef-animation-name title=animation-name>animation-name</a> value and
not necessarily for each property being animated.
<p> Any animation for which both a valid keyframe rule and a non-zero duration are defined will run
and generate events; this includes animations with empty keyframe rules.
<p> Issue: This contradicts the <a class=property data-link-type=propdesc href=#propdef-animation-delay title=animation-delay>animation-delay</a> section,
which says that a <span class=css data-link-type=maybe title=0s>0s</span> duration animation still fires events.
<p> The time the animation h
108B8
as been running is sent with each event generated. This allows the event
handler to determine the current iteration of a looping animation or the current position of an
alternating animation. This time does not include any time the animation was in the <a class=css data-link-type=maybe href=#valuedef-paused title=paused>paused</a>
play state.
<h3 class="heading settled heading" data-level=5.1 id=interface-animationevent><span class=secno>5.1 </span><span class=content>
The <code>AnimationEvent</code> Interface</span><a class=self-link href=#interface-animationevent></a></h3>
<p> The <dfn data-dfn-type=dfn data-noexport="" id=animationevent>AnimationEvent<a class=self-link href=#animationevent></a></dfn> interface provides specific contextual information associated with
Animation events.
<h4 class="heading settled heading" data-level=5.1.1 id=interface-animationevent-idl><span class=secno>5.1.1 </span><span class=content>
IDL Definition</span><a class=self-link href=#interface-animationevent-idl></a></h4>
<pre class=idl>[Constructor(DOMString <dfn class=idl-code data-dfn-for=AnimationEvent/AnimationEvent() data-dfn-type=argument data-export="" data-global-name="AnimationEvent<interface>/AnimationEvent()<method>/type<argument>" id=dom-animationeventanimationevent-type>type<a class=self-link href=#dom-animationeventanimationevent-type></a></dfn>, optional <a data-link-type=idl href=#dictdef-animationeventinit title=animationeventinit>AnimationEventInit</a> <dfn class=idl-code data-dfn-for=AnimationEvent/AnimationEvent() data-dfn-type=argument data-export="" data-global-name="AnimationEvent<interface>/AnimationEvent()<method>/animationeventinitdict<argument>" id=dom-animationeventanimationevent-animationeventinitdict>animationEventInitDict<a class=self-link href=#dom-animationeventanimationevent-animationeventinitdict></a></dfn>)]
interface <dfn class=idl-code data-dfn-type=interface data-export="" data-global-name="" id=dom-animationevent>AnimationEvent<a class=self-link href=#dom-animationevent></a></dfn> : <a data-link-type=idl href=http://dom.spec.whatwg.org/#event title=event>Event</a> {
readonly attribute DOMString <dfn class=idl-code data-dfn-for=AnimationEvent data-dfn-type=attribute data-export="" data-global-name="AnimationEvent<interface>/animationname<attribute>" id=dom-animationevent-animationname0>animationName<a class=self-link href=#dom-animationevent-animationname0></a></dfn>;
readonly attribute float <dfn class=idl-code data-dfn-for=AnimationEvent data-dfn-type=attribute data-export="" data-global-name="AnimationEvent<interface>/elapsedtime<attribute>" id=dom-animationevent-elapsedtime0>elapsedTime<a class=self-link href=#dom-animationevent-elapsedtime0></a></dfn>;
readonly attribute DOMString <dfn class=idl-code data-dfn-for=AnimationEvent data-dfn-type=attribute data-export="" data-global-name="AnimationEvent<interface>/pseudoelement<attribute>" id=dom-animationevent-pseudoelement0>pseudoElement<a class=self-link href=#dom-animationevent-pseudoelement0></a></dfn>;
};
dictionary <dfn class=idl-code data-dfn-type=dictionary data-export="" data-global-name="" id=dictdef-animationeventinit>AnimationEventInit<a class=self-link href=#dictdef-animationeventinit></a></dfn> : <a data-link-type=idl href=http://dom.spec.whatwg.org/#eventinit title=eventinit>EventInit</a> {
DOMString <dfn class=idl-code data-dfn-for=AnimationEventInit data-dfn-type=dict-member data-export="" data-global-name="AnimationEventInit<dictionary>/animationname<dict-member>" id=dom-animationeventinit-animationname>animationName<a class=self-link href=#dom-animationeventinit-animationname></a></dfn> = "";
float <dfn class=idl-code data-dfn-for=AnimationEventInit data-dfn-type=dict-member data-export="" data-global-name="AnimationEventInit<dictionary>/elapsedtime<dict-member>" id=dom-animationeventinit-elapsedtime>elapsedTime<a class=self-link href=#dom-animationeventinit-elapsedtime></a></dfn> = 0.0;
DOMString <dfn class=idl-code data-dfn-for=AnimationEventInit data-dfn-type=dict-member data-export="" data-global-name="AnimationEventInit<dictionary>/pseudoelement<dict-member>" id=dom-animationeventinit-pseudoelement>pseudoElement<a class=self-link href=#dom-animationeventinit-pseudoelement></a></dfn> = "";
};
</pre>
<h4 class="heading settled heading" data-level=5.1.2 id=interface-animationevent-attributes><span class=secno>5.1.2 </span><span class=content>
Attributes</span><a class=self-link href=#interface-animationevent-attributes></a></h4>
<dl data-dfn-for=animationevent data-dfn-type=attribute>
<dt><dfn class=idl-code data-dfn-for=animationevent data-dfn-type=attribute data-export="" id=dom-animationevent-animationname>animationName<a class=self-link href=#dom-animationevent-animationname></a></dfn>, of type <a class=idl-code data-link-type=interface title=domstring>DOMString</a>, readonly
<dd>
The value of the <a class=property data-link-type=propdesc href=#propdef-animation-name title=animation-name>animation-name</a> property of the animation that fired the event.
<dt><dfn class=idl-code data-dfn-for=animationevent data-dfn-type=attribute data-export="" id=dom-animationevent-elapsedtime>elapsedTime<a class=self-link href=#dom-animationevent-elapsedtime></a></dfn>, of type float, readonly
<dd>
The amount of time the animation has been running, in seconds, when this event fired,
excluding any time the animation was paused. For an <span class=css data-link-type=maybe title=animationstart>animationstart</span> event, the
elapsedTime is zero unless there was a negative value for <a class=property data-link-type=propdesc href=#propdef-animation-delay title=animation-delay>animation-delay</a>, in which
case the event will be fired with an elapsedTime of (-1 * delay).
<dt><dfn class=idl-code data-dfn-for=animationevent data-dfn-type=attribute data-export="" id=dom-animationevent-pseudoelement>pseudoElement<a class=self-link href=#dom-animationevent-pseudoelement></a></dfn>, of type <a class=idl-code data-link-type=interface title=domstring>DOMString</a>, readonly
<dd>
The name (beginning with two colons) of the CSS pseudo-element on which the animation
runs (in which case the target of the event is that pseudo-element’s corresponding
element), or the empty string if the animation runs on an element (which means the
target of the event is that element).
</dl>
<p> <dfn class=css-code data-dfn-type=function data-export="" id=funcdef-animationevent title=animationevent()>AnimationEvent(type, animationEventInitDict)<a class=self-link href=#funcdef-animationevent></a></dfn> is an <a href=http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#constructing-events>event constructor</a>.
<h3 class="heading settled heading" data-level=5.2 id=event-animationevent><span class=secno>5.2 </span><span class=content>
Types of <code>AnimationEvent</code></span><a class=self-link href=#event-animationevent></a></h3>
<p> The different types of animation events that can occur are:
<dl data-dfn-for=animationevent data-dfn-type=event>
<dt><dfn class=idl-code data-dfn-for=animationevent data-dfn-type=event data-export="" id=dom-animationevent-animationstart>animationstart<a class=self-link href=#dom-animationevent-animationstart></a></dfn>
<dd>
The <a data-link-type=idl href=#dom-animationevent-animationstart title=animationstart>animationstart</a> event occurs at the start of the animation. If there is an
<a class=property data-link-type=propdesc href=#propdef-animation-delay title=animation-delay>animation-delay</a> then this event will fire once the delay period has expired.
A negative delay will cause the event to fire with an elapsedTime equal to the
absolute value of the delay.
<ul>
<li>Bubbles: Yes</li>
<li>Cancelable: No</li>
<li>Context Info: animationName, pseudoElement</li>
</ul>
<dt><dfn class=idl-code data-dfn-for=animationevent data-dfn-type=event data-export="" id=dom-animationevent-animationend>animationend<a class=self-link href=#dom-animationevent-animationend></a></dfn>
<dd>
The <a data-link-type=idl href=#dom-animationevent-animationend title=animationend>animationend</a> event occurs when the animation finishes.
<ul>
<li>Bubbles: Yes</li>
<li>Cancelable: No</li>
<li>Context Info: animationName, elapsedTime, pseudoElement</li>
</ul>
<dt><dfn class=idl-code data-dfn-for=animationevent data-dfn-type=event data-export="" id=dom-animationevent-animationiteration>animationiteration<a class=self-link href=#dom-animationevent-animationiteration></a></dfn>
<dd>
The <a data-link-type=idl href=#dom-animationevent-animationiteration title=animationiteration>animationiteration</a> event occurs at the end of each iteration of an
animation, except when an animationend event would fire at the same time.
This means that this event does not occur for animations with an iteration
count of one or less.
<ul>
<li>Bubbles: Yes</li>
<li>Cancelable: No</li>
<li>Context Info: animationName, elapsedTime, pseudoElement</li>
</ul>
</dl>
<h2 class="heading settled heading" data-level=6 id=interface-dom><span class=secno>6 </span><span class=content>
DOM Interfaces</span><a class=self-link href=#interface-dom></a></h2>
<p> CSS animations are exposed to the CSSOM through a pair of new interfaces describing the keyframes.
<h3 class="heading settled heading" data-level=6.1 id=interface-cssrule><span class=secno>6.1 </span><span class=content>
The <code>CSSRule</code> Interface</span><a class=self-link href=#interface-cssrule></a></h3>
<p> The following two rule types are added to the <a data-link-type=idl href=http://dev.w3.org/csswg/cssom-1/#cssrule title=cssrule>CSSRule</a> interface. They provide
identification for the new keyframe and keyframes rules.
<h4 class="heading settled heading" data-level=6.1.1 id=interface-cssrule-idl><span class=secno>6.1.1 </span><span class=content>
IDL Definition</span><a class=self-link href=#interface-cssrule-idl></a></h4>
<pre class=idl>partial interface <a class=idl-code data-global-name="" data-link-type=interface href=http://dev.w3.org/csswg/cssom-1/#cssrule title=cssrule>CSSRule</a> {
const unsigned short <dfn class=idl-code data-dfn-for=CSSRule data-dfn-type=const data-export="" data-global-name="CSSRule<interface>/keyframes_rule<const>" id=dom-cssrule-keyframes_rule>KEYFRAMES_RULE<a class=self-link href=#dom-cssrule-keyframes_rule></a></dfn> = 7;
const unsigned short <dfn class=idl-code data-dfn-for=CSSRule data-dfn-type=const data-export="" data-global-name="CSSRule<interface>/keyframe_rule<const>" id=dom-cssrule-keyframe_rule>KEYFRAME_RULE<a class=self-link href=#dom-cssrule-keyframe_rule></a></dfn> = 8;
};
</pre>
<h3 class="heading settled heading" data-level=6.2 id=interface-csskeyframerule><span class=secno>6.2 </span><span class=content>
The <code>CSSKeyframeRule</code> Interface</span><a class=self-link href=#interface-csskeyframerule></a></h3>
<p> The <a data-link-type=idl href=#dom-csskeyframerule title=csskeyframerule>CSSKeyframeRule</a> interface represents the style rule for a single key.
<h4 class="heading settled heading" data-level=6.2.1 id=interface-csskeyframerule-idl><span class=secno>6.2.1 </span><span class=content>
IDL Definition</span><a class=self-link href=#interface-csskeyframerule-idl></a></h4>
<pre class=idl>interface <dfn class=idl-code data-dfn-type=interface data-export="" data-global-name="" id=dom-csskeyframerule>CSSKeyframeRule<a class=self-link href=#dom-csskeyframerule></a></dfn> : <a data-link-type=idl href=http://dev.w3.org/csswg/cssom-1/#cssrule title=cssrule>CSSRule</a> {
attribute DOMString <dfn class=idl-code data-dfn-for=CSSKeyframeRule data-dfn-type=attribute data-export="" data-global-name="CSSKeyframeRule<interface>/keytext<attribute>" id=dom-csskeyframerule-keytext>keyText<a class=self-link href=#dom-csskeyframerule-keytext></a></dfn>;
readonly attribute <a data-link-type=idl href=http://dev.w3.org/csswg/cssom-1/#cssstyledeclaration title=cssstyledeclaration>CSSStyleDeclaration</a> <dfn class=idl-code data-dfn-for=CSSKeyframeRule data-dfn-type=attribute data-export="" data-global-name="CSSKeyframeRule<interface>/style<attribute>" id=dom-csskeyframerule-style0>style<a class=self-link href=#dom-csskeyframerule-style0></a></dfn>;
};
</pre>
<h4 class="heading settled heading" data-level=6.2.2 id=interface-csskeyframerule-attributes><span class=secno>6.2.2 </span><span class=content>
Attributes</span><a class=self-link href=#interface-csskeyframerule-attributes></a></h4>
<dl data-dfn-for=csskeyframerule data-dfn-type=attribute>
<dt><dfn class=idl-code data-dfn-for=CSSKeyFramesRule data-dfn-type=attribute data-export="" id=dom-csskeyframesrule-keytext>keyText<a class=self-link href=#dom-csskeyframesrule-keytext></a></dfn>, of type <a class=idl-code data-link-type=interface title=domstring>DOMString</a>
<dd>
This attribute represents the keyframe selector as a comma-separated list of
percentage values. The <span class=css data-link-type=maybe title=from>from</span> and <span class=css data-link-type=maybe title=to>to</span> keywords map to 0% and 100%,
respectively.
<p> If <a class=idl-code data-link-for=CSSKeyFramesRule data-link-type=attribute href=#dom-csskeyframesrule-keytext title=keytext>keyText</a> is updated with an invalid keyframe selector,
a <a data-link-spec=dom-core-ls data-link-type=dfn href=http://dom.spec.whatwg.org/#syntaxerror title=syntaxerror>SyntaxError</a> exception must be thrown.
<dt><dfn class=idl-code data-dfn-for=csskeyframerule data-dfn-type=attribute data-export="" id=dom-csskeyframerule-style>style<a class=self-link href=#dom-csskeyframerule-style></a></dfn>, of type <a class=idl-code data-link-type=interface href=http://dev.w3.org/csswg/cssom-1/#cssstyledeclaration title=cssstyledeclaration>CSSStyleDeclaration</a>
<dd>
This attribute represents the style associated with this keyframe.
</dl>
<h3 class="heading settled heading" data-level=6.3 id=interface-csskeyframesrule><span class=secno>6.3 </span><span class=content>
The <code>CSSKeyframesRule</code> Interface</span><a class=self-link href=#interface-csskeyframesrule></a></h3>
<p> The <a data-link-type=idl href=#dom-csskeyframesrule title=csskeyframesrule>CSSKeyframesRule</a> interface represents a complete set of keyframes for
a single animation.
<h4 class="heading settled heading" data-level=6.3.1 id=interface-csskeyframesrule-idl><span class=secno>6.3.1 </span><span class=content>
IDL Definition</span><a class=self-link href=#interface-csskeyframesrule-idl></a></h4>
<pre class=idl>interface <dfn class=idl-code data-dfn-type=interface data-export="" data-global-name="" id=dom-csskeyframesrule>CSSKeyframesRule<a class=self-link href=#dom-csskeyframesrule></a></dfn> : <a data-link-type=idl href=http://dev.w3.org/csswg/cssom-1/#cssrule title=cssrule>CSSRule</a> {
attribute DOMString <dfn class=idl-code data-dfn-for=CSSKeyframesRule data-dfn-type=attribute data-export="" data-global-name="CSSKeyframesRule<interface>/name<attribute>" id=dom-csskeyframesrule-name0>name<a class=self-link href=#dom-csskeyframesrule-name0></a></dfn>;
readonly attribute <a data-link-type=idl href=http://dev.w3.org/csswg/cssom-1/#cssrulelist title=cssrulelist>CSSRuleList</a> <dfn class=idl-code data-dfn-for=CSSKeyframesRule data-dfn-type=attribute data-export="" data-global-name="CSSKeyframesRule<interface>/cssrules<attribute>" id=dom-csskeyframesrule-cssrules0>cssRules<a class=self-link href=#dom-csskeyframesrule-cssrules0></a></dfn>;
void <dfn class=idl-code data-dfn-for=CSSKeyframesRule data-dfn-type=method data-export="" data-global-name="CSSKeyframesRule<interface>/appendrule()<method>" id=dom-csskeyframesrule-appendrule0 title=appendRule()>appendRule<a class=self-link href=#dom-csskeyframesrule-appendrule0></a></dfn>(in DOMString <dfn class=idl-code data-dfn-for=CSSKeyframesRule/appendRule() data-dfn-type=argument data-export="" data-global-name="CSSKeyframesRule<interface>/appendRule()<method>/rule<argument>" id=dom-csskeyframesruleappendrule-rule0>rule<a class=self-link href=#dom-csskeyframesruleappendrule-rule0></a></dfn>);
void <dfn class=idl-code data-dfn-for=CSSKeyframesRule data-dfn-type=method data-export="" data-global-name="CSSKeyframesRule<interface>/deleterule()<method>" id=dom-csskeyframesrule-deleterule0 title=deleteRule()>deleteRule<a class=self-link href=#dom-csskeyframesrule-deleterule0></a></dfn>(in DOMString <dfn class=idl-code data-dfn-for=CSSKeyframesRule/deleteRule() data-dfn-type=argument data-export="" data-global-name="CSSKeyframesRule<interface>/deleteRule()<method>/key<argument>" id=dom-csskeyframesruledeleterule-key0>key<a class=self-link href=#dom-csskeyframesruledeleterule-key0></a></dfn>);
<a data-link-type=idl href=#dom-csskeyframerule title=csskeyframerule>CSSKeyframeRule</a> <dfn class=idl-code data-dfn-for=CSSKeyframesRule data-dfn-type=method data-export="" data-global-name="CSSKeyframesRule<interface>/findrule()<method>" id=dom-csskeyframesrule-findrule0 title=findRule()>findRule<a class=self-link href=#dom-csskeyframesrule-findrule0></a></dfn>(in DOMString <dfn class=idl-code data-dfn-for=CSSKeyframesRule/findRule() data-dfn-type=argument data-export="" data-global-name="CSSKeyframesRule<interface>/findRule()<method>/key<argument>" id=dom-csskeyframesrulefindrule-key0>key<a class=self-link href=#dom-csskeyframesrulefindrule-key0></a></dfn>);
};
</pre>
<h4 class="heading settled heading" data-level=6.3.2 id=interface-csskeyframesrule-attributes><span class=secno>6.3.2 </span><span class=content>
Attributes</span><a class=self-link href=#interface-csskeyframesrule-attributes></a></h4>
<dl data-dfn-for=csskeyframesrule data-dfn-type=attribute>
<dt><dfn class=idl-code data-dfn-for=csskeyframesrule data-dfn-type=attribute data-export="" id=dom-csskeyframesrule-name>name<a class=self-link href=#dom-csskeyframesrule-name></a></dfn>, of type <a class=idl-code data-link-type=interface title=domstring>DOMString</a>
<dd>
This attribute is the name of the keyframes, used by the <a class=property data-link-type=propdesc href=#propdef-animation-name title=animation-name>animation-name</a> property.
<dt><dfn class=idl-code data-dfn-for=csskeyframesrule data-dfn-type=attribute data-export="" id=dom-csskeyframesrule-cssrules>cssRules<a class=self-link href=#dom-csskeyframesrule-cssrules></a></dfn>, of type <a class=idl-code data-link-type=interface href=http://dev.w3.org/csswg/cssom-1/#cssrulelist title=cssrulelist>CSSRuleList</a>
<dd>
This attribute gives access to the keyframes in the list.
</dl>
<h4 class="heading settled heading" data-level=6.3.3 id=interface-csskeyframesrule-appendrule><span class=secno>6.3.3 </span><span class=content>
The <code>appendRule</code> method</span><a class=self-link href=#interface-csskeyframesrule-appendrule></a></h4>
<p> The <dfn class=idl-code data-dfn-for=CSSKeyFramesRule data-dfn-type=method data-export="" id=dom-csskeyframesrule-appendrule title=appendrule()>appendRule()<a class=self-link href=#dom-csskeyframesrule-appendrule></a></dfn> method appends the passed
<a data-link-type=idl href=#dom-csskeyframerule title=csskeyframerule>CSSKeyframeRule</a> into the list at the passed key.
<p> Parameters:
<dl>
<dt><dfn class=idl-code data-dfn-for=CSSKeyFramesRule/appendRule() data-dfn-type=argument data-export="" id=dom-csskeyframesruleappendrule-rule>rule<a class=self-link href=#dom-csskeyframesruleappendrule-rule></a></dfn> of type <a class=idl-code data-link-type=interface title=domstring>DOMString</a>
<dd>
The rule to be appended, expressed in the same syntax as one entry in the
<a class=css data-link-type=maybe href=#at-ruledef-keyframes title=@keyframes>@keyframes</a> rule.
</dl>
<p> No Return Value
<p> No Exceptions