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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN"
"http://www.w3.org/TR/html4/strict.dtd">
<html lang=en>
<head>
<title>CSS Animations Module Level 3</title>
<link href=default.css rel=stylesheet type="text/css">
<style type="text/css">
.rhs { white-space: pre-wrap; }
code { font-size: inherit; }
#box-shadow-samples td { background: white; color: black; }
table {
border-collapse: collapse;
}
td {
padding: 0.2em 1em;
border: 1px solid black;
}
</style>
<link href="http://www.w3.org/StyleSheets/TR/W3C-ED.css" rel=stylesheet
type="text/css">
<body>
<div class=head> <!--begin-logo-->
<p><a href="http://www.w3.org/"><img alt=W3C height=48
src="http://www.w3.org/Icons/w3c_home" width=72></a> <!--end-logo-->
<h1>CSS Animations Module Level 3</h1>
<h2 class="no-num no-toc" id=longstatus-date>Editor's Draft 23 August 2010</h2>
<dl>
<dt>This version:
<dd><a
href="http://www.w3.org/TR/2010/ED-css3-animations-20100823">http://dev.w3.org/csswg/css3-animations/</a>
<!--http://www.w3.org/TR/2010/WD-css3-animations-20100823-->
<dt>Latest version:
<dd><a
href="http://www.w3.org/TR/css3-animations">http://www.w3.org/TR/css3-animations</a>
<dt>Previous version:
<dd><a href="http://www.w3.org/TR/2009/WD-css3-animations-20090320/">
http://www.w3.org/TR/2009/WD-css3-animations-20090320/</a>
<dt id=editors-list>Editors:
<dd><a href="mailto:dino@apple.com">Dean Jackson</a> (<a
href="http://www.apple.com/">Apple Inc</a>)
<dd><a href="mailto:hyatt@apple.com">David Hyatt</a> (<a
href="http://www.apple.com/">Apple Inc</a>)
<dd><a href="mailto:cmarrin@apple.com">Chris Marrin</a> (<a
href="http://www.apple.com/">Apple Inc</a>)
</dl>
<!--begin-copyright-->
<p class=copyright><a
href="http://www.w3.org/Consortium/Legal/ipr-notice#Copyright"
rel=license>Copyright</a> © 2010 <a
href="http://www.w3.org/"><acronym title="World Wide Web
Consortium">W3C</acronym></a><sup>®</sup> (<a
href="http://www.csail.mit.edu/"><acronym title="Massachusetts Institute
of Technology">MIT</acronym></a>, <a href="http://www.ercim.eu/"><acronym
title="European Research Consortium for Informatics and
Mathematics">ERCIM</acronym></a>, <a
href="http://www.keio.ac.jp/">Keio</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>
<!--end-copyright-->
<hr title="Separator for header">
</div>
<h2 class="no-num no-toc" id=abstract>Abstract</h2>
<p>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.
<h2 class="no-num no-toc" id=status>Status of this document</h2>
<!--begin-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=%5Bcss3-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
“css3-animations” in the subject, preferably like this:
“[<!---->css3-animations<!---->] <em>…summary of
comment…</em>”
<p>This document was produced by the <a href="/Style/CSS/members">CSS
Working Group</a> (part of the <a href="/Style/">Style Activity</a>).
<p>This document was produced by a group operating under the <a
href="/Consortium/Patent-Policy-20040205/">5 February 2004 W3C Patent
Policy</a>. W3C maintains a <a href="/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="/Consortium/Patent-Policy-20040205/#def-essential">Essential
Claim(s)</a> must disclose the information in accordance with <a
href="/Consortium/Patent-Policy-20040205/#sec-Disclosure">section 6 of the
W3C Patent Policy</a>.</p>
<!--end-status-->
<h2 class="no-num no-toc" id=contents>Table of contents</h2>
<!--begin-toc-->
<ul class=toc>
<li><a href="#introduction"><span class=secno>1. </span>Introduction</a>
<li><a href="#animations"><span class=secno>2. </span>Animations</a>
<li><a href="#keyframes"><span class=secno>3. </span>Keyframes</a>
<ul class=toc>
<li><a href="#timing-functions-for-keyframes-"><span class=secno>3.1.
</span> Timing functions for keyframes </a>
<li><a href="#the-animation-name-property-"><span class=secno>3.2.
</span> The <span class=prop-name>‘<code
class=property>animation-name</code>’</span> Property </a>
<li><a href="#the-animation-duration-property-"><span class=secno>3.3.
</span> The <span class=prop-name>‘<code
class=property>animation-duration</code>’</span> Property </a>
<li><a href="#animation-timing-function_tag"><span class=secno>3.4.
</span> The <span class=prop-name>‘<code
class=property>animation-timing-function</code>’</span> Property
</a>
<li><a href="#the-animation-iteration-count-property-"><span
class=secno>3.5. </span> The <span class=prop-name>‘<code
class=property>animation-iteration-count</code>’</span> Property
</a>
<li><a href="#the-animation-direction-property-"><span class=secno>3.6.
</span> The <span class=prop-name>‘<code
class=property>animation-direction</code>’</span> Property </a>
<li><a href="#the-animation-play-state-property-"><span class=secno>3.7.
</span> The <span class=prop-name>‘<code
class=property>animation-play-state</code>’</span> Property </a>
<li><a href="#the-animation-delay-property-"><span class=secno>3.8.
</span> The <span class=prop-name>‘<code
class=property>animation-delay</code>’</span> Property </a>
<li><a href="#the-animation-fill-mode-property-"><span class=secno>3.9.
</span> The <span class=prop-name>‘<code
class=property>animation-fill-mode</code>’</span> Property </a>
<li><a href="#the-animation-shorthand-property-"><span class=secno>3.10.
</span> The <span class=prop-name>‘<code
class=property>animation</code>’</span> Shorthand Property </a>
</ul>
<li><a href="#animation-events-"><span class=secno>4. </span> Animation
Events </a>
<li><a href="#dom-interfaces-"><span class=secno>5. </span> DOM Interfaces
</a>
<li><a href="#references"><span class=secno>6. </span>References</a>
<ul class=toc>
<li class=no-num><a href="#normative-references">Normative
references</a>
<li class=no-num><a href="#other-references">Other references</a>
</ul>
<li class=no-num><a href="#property-index">Property index</a>
<li class=no-num><a href="#index">Index</a>
</ul>
<!--end-toc-->
<h2 id=introduction><span class=secno>1. </span>Introduction</h2>
<p><em>This section is not normative.</em>
<p> CSS Transitions <a href="#CSS3-TRANSITIONS"
rel=biblioentry>[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 <em>defined animations</em>, 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 <i>implicitly</i> when property values
change, animations are <i>explicitly</i> 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 id=animations><span class=secno>2. </span>Animations</h2>
<p> CSS Animations affect computed property values. During the execution of
an animation, the computed value for a property is controlled by the
animation. This overrides the value specified in the normal styling
system.
<p> In the case of multiple animations specifying behavior for the same
property, the animation defined last will override the previously defined
animations.
<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.
<div class=figure> <img alt="" src=sandwich.png></div>
<p class=caption> Computation of animated property values
<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 latter of two moments: the time
at which the style is resolved that specifies the animation, or the time
the document's load event is fired. Therefore, an animation specified in
the document stylesheet will begin at the document load. An animation
specified on an element by modifying the style after the document has
loaded will start when the 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).
<p> An animation applies to an element if the element has a value for <span
class=prop-name>‘<a href="#animation-name"><code
class=property>animation-name</code></a>’</span> that references a
valid keyframes rule. Once an animation has started it continues until it
ends or the <span class=prop-name>‘<a href="#animation-name"><code
class=property>animation-name</code></a>’</span> 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 <span
class=prop-name>‘<a href="#animation-name"><code
class=property>animation-name</code></a>’</span> 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 <span
class=prop-name>‘<a href="#animation-duration"><code
class=property>animation-duration</code></a>’</span>, <span
class=prop-name>‘<a href="#animation-iteration-count"><code
class=property>animation-iteration-count</code></a>’</span> and
&
8096
lt;span class=prop-name>‘<a href="#animation-fill-mode"><code
class=property>animation-fill-mode</code></a>’</span> properties.
<div class=example>
<p style="display:none"> Example(s):</p>
<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>
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>
<h2 id=keyframes><span class=secno>3. </span>Keyframes</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 <span
class=prop-name>@keyframes</span> rule consists of the keyword
"@keyframes", followed by an identifier giving a name for the animation
(which will be referenced using <span class=prop-name>‘<a
href="#animation-name"><code
class=property>animation-name</code></a>’</span>), followed by a set
of style rules (delimited by curly braces).
<p> The <i>keyframe selector</i> for a keyframe style rule consists of a
comma-separated list of percentage values or the keywords ‘<code
class=property>from</code>’ or ‘<code
class=property>to</code>’. 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 ‘<code
class=property>from</code>’ is equivalent to the value 0%. The
keyword ‘<code class=property>to</code>’ is equivalent to the
value 100%. Note that the percentage unit specifier must be used on
percentage values. Therefore, "0" is an invalid keyframe selector.
<p> If a 0% or "from" keyframe is not specified, then the user agent
constructs a 0% keyframe using the computed values of the properties being
animated. If a 100% or "to" keyframe is not specified, then the user agent
constructs a 100% keyframe using the computed values of the properties
being animated.
<p class=issue> ISSUE: how does this work with repeating animations?
<p> The <i>keyframe declaration</i> 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=prop-name
href="#animation-timing-function">animation-timing-function'</a>, the
behavior of which is described below.
<p class=note> NOTE: 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 <span class=prop-name>‘<a
href="#animation-name"><code
class=property>animation-name</code></a>’</span> property. <span
class=prop-name>@keyframes</span> rules do not cascade; therefore an
animation will never derive keyframes from more than one <span
class=prop-name>@keyframes</span> rule.
<p> To determine the set of keyframes, all of the values in selectors are
sorted in increasing order by time. If there are any duplicates, then the
last keyframe specified inside the <span class=prop-name>@keyframes</span>
rule will be used to provide the keyframe information for that time. There
is no cascading within a <span class=prop-name>@keyframes</span> rule if
multiple keyframes specify the same keyframe selector values.
<div class=example>
<p style="display:none"> Example(s):</p>
<pre>
@keyframes wobble {
0% {
left: 100px;
}
40% {
left: 150px;
}
60% {
left: 75px;
}
100% {
left: 100px;
}
}
</pre>
Four keyframes are specified for the animation named "wobble". In the
first keyframe, shown at the beginning of the animation cycle, the
‘<code class=property>left</code>’ value of the animation is
100px. By 40% of the animation duration, ‘<code
class=property>left</code>’ value has animated to 150px. At 60% of
the animation duration, the ‘<code class=property>left</code>’
value has animated back to 75px. At the end of the animation cycle, the
‘<code class=p
133E
roperty>left</code>’ value has returned to
100px. The diagram below shows the state of the animation if it were given
a duration of 10s.
<div class=figure> <img alt="" src=animation1.png></div>
<p class=caption> Animations states specified by keyframes</p>
</div>
<p> The following is the grammar for the keyframes rule.
<pre>
keyframes-rule: '@keyframes' IDENT '{' keyframes-blocks '}';
keyframes-blocks: [ keyframe-selectors block ]* ;
keyframe-selectors: [ 'from' | 'to' | PERCENTAGE ] [ ',' [ 'from' | 'to' | PERCENTAGE ] ]*;
</pre>
<!-- ======================================================================================================= -->
<h3 id=timing-functions-for-keyframes-><span class=secno>3.1. </span>
Timing functions for keyframes</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>
<p style="display:none"> Example(s):</p>
<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>
Five keyframes are specified for the animation named "bounce". Between the
first and second keyframe (ie. between 0 and 25%) an "ease-out" timing
function is used. Between the second and third keyframe (ie. 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 units up the page. A timing function specified on the
"to" or 100% keyframe is ignored</div>
<p> See <a href="#animation-timing-function_tag">the <span
class=prop-name>‘<code
class=property>animation-timing-function</code>’</span> property</a>
for more information.</p>
<!-- ======================================================================================================= -->
<!-- ======================================================================================================= -->
<h3 id=the-animation-name-property-><span class=secno>3.2. </span> The
<span class=prop-name>‘<a href="#animation-name"><code
class=property>animation-name</code></a>’</span> Property</h3>
<p> The <span class=prop-name>‘<a href="#animation-name"><code
class=property>animation-name</code></a>’</span> 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 class=property>none</code>’ then there will be
no animation. This can be used to override any animations coming from the
cascade.
<table class=propdef>
<tbody>
<tr>
<td> <em>Name:</em>
<td> <dfn id=animation-name>animation-name</dfn>
<tr>
<td> <em>Value:</em>
<td> none | IDENT [, none | IDENT ]*
<tr>
<td> <em>Initial:</em>
<td> none
<tr>
<td> <em>Applies to:</em>
<td> block-level and inline-level elements
<tr>
<td> <em>Inherited:</em>
<td> no
<tr>
<td> <em>Percentages:</em>
<td> N/A
<tr>
<td> <em>Media:</em>
<td> visual
<tr>
<td> <em>Computed value:</em>
<td> Same as specified value.
</table>
<!--
<p>
It is possible for elements to have multiple animations running that change the same property or properties. In this case the animations combine in a manner defined by the property. For example, animations on <span class="prop-name">opacity</span> will add together and animations on <span class="prop-name">transform</span> will have their transformation matrices multiplied.
</p>
<div class="example">
<p style="display:none">
Example(s):
</p>
<pre>
@keyframes 'border-bloat' {
from {
border-width: 0;
}
to {
border-width: 10px;
}
}
@keyframes 'border-diet' {
from {
border-width: 4px;
}
to {
border-width: 2px;
}
}
div {
animation-name: 'border-bloat', 'border-diet';
animation-duration: 10s, 4s;
}
</pre>
<p>
The above example has two animations executing on the same property, <span class="prop-name">border-width</span>. The animations are additive. That is, the
resulting value for the property will be the addition of the values from the
two animations.
</p>
<p>
At time ‘<code class=css>0s</code>’ the element's border will be 4px wide (0px from ‘<code class=property>border-bloat</code>’ plus 4px from ‘<code class=property>border-diet</code>’).
At time ‘<code class=css>4s</code>’ the element's border will be 6px wide (4px from ‘<code class=property>border-bloat</code>’ plus 2px from ‘<code class=property>border-diet</code>’).
At time ‘<code class=css>10s</code>’ the element's border will be 10px wide (10px from ‘<code class=property>border-bloat</code>’ and no addition from
‘<code class=property>border-diet</code>’ as it is no longer executing).
</p>
</div>
-->
<!-- ======================================================================================================= -->
<h3 id=the-animation-duration-property-><span class=secno>3.3. </span> The
<span class=prop-name>‘<a href="#animation-duration"><code
class=property>animation-duration</code></a>’</span> Property</h3>
<p> The <span class=prop-name>‘<a href="#animation-duration"><code
class=property>animation-duration</code></a>’</span> property
defines the length of time that an animation takes to complete one cycle.
<table class=propdef>
<tbody>
<tr>
<td> <em>Name:</em>
<td> <dfn id=animation-duration>animation-duration</dfn>
<tr>
<td> <em>Value:</em>
<td> <time> [, <time>]*
<tr>
<td> <em>Initial:</em>
<td> 0
<tr>
<td> <em>Applies to:</em>
<td> block-level and inline-level elements
<tr>
<td> <em>Inherited:</em>
<td> no
<tr>
<td> <em>Percentages:</em>
<td> N/A
<tr>
<td> <em>Media:</em>
<td> visual
<tr>
<td> <em>Computed value:</em>
<td> Same as specified value.
</table>
<p> By default the value is ‘<code class=css>0</code>’, meaning
that the animation cycle is immediate (i.e. there will be no animation). A
negative value for <a class=prop-name
href="#animation-duration">animation-duration</a> is treated as
‘<code class=css>0</code>’.</p>
<!-- ======================================================================================================= -->
<h3 id="animation-timing-function_tag"><span class=secno>3.4. </span> The
<span class=prop-name>‘<a href="#animation-timing-function"><code
class=property>animation-timing-function</code></a>’</span> Property
</h3>
<p> The <span class=prop-name>‘<a
href="#animation-timing-function"><code
class=property>animation-timing-function</code></a>’</span> property
describes how the animation will progress over one cycle of its duration.
See the <span class=prop-name>‘<code
class=property>transition-timing-function</code>’</span> property <a
href="#CSS3-TRANSITIONS"
rel=biblioentry>[CSS3-TRANSITIONS]<!--{{!CSS3-TRANSITIONS}}--></a> for a
complete description of timing function calculation.
<table class=propdef>
<tbody>
<tr>
<td> <em>Name:</em>
<td> <dfn id=animation-timing-function>animation-timing-function</dfn>
<tr>
<td> <em>Value:</em>
<td> ease | linear |
133E
ease-in | ease-out | ease-in-out | step-start |
step-end | steps(<number>[, start | end ]) |
cubic-bezier(<number>, <number>, <number>,
<number>) [, ease | linear | ease-in | ease-out | ease-in-out |
step-start | step-end | steps(<number>[, start | end ]) |
cubic-bezier(<number>, <number>, <number>,
<number>)]*
<tr>
<td> <em>Initial:</em>
<td> ease
<tr>
<td> <em>Applies to:</em>
<td> block-level and inline-level elements
<tr>
<td> <em>Inherited:</em>
<td> no
<tr>
<td> <em>Percentages:</em>
<td> N/A
<tr>
<td> <em>Media:</em>
<td> visual
<tr>
<td> <em>Computed value:</em>
<td> Same as specified value.
</table>
<p> For a keyframed animation, the <span class=prop-name>‘<a
href="#animation-timing-function"><code
class=property>animation-timing-function</code></a>’</span> applies
between keyframes, not over the entire animation. For example, in the case
of an ease-in-out timing function, an animation will ease in at the start
of the keyframe and ease out at the end of the keyframe. A <span
class=prop-name>‘<a href="#animation-timing-function"><code
class=property>animation-timing-function</code></a>’</span> defined
within a keyframe block applies to that keyframe, otherwise the timing
function specified for the animation is used.</p>
<!-- ======================================================================================================= -->
<h3 id=the-animation-iteration-count-property-><span class=secno>3.5.
</span> The <span class=prop-name>‘<a
href="#animation-iteration-count"><code
class=property>animation-iteration-count</code></a>’</span> Property
</h3>
<p> The <span class=prop-name>‘<a
href="#animation-iteration-count"><code
class=property>animation-iteration-count</code></a>’</span> property
defines the number of times an animation cycle is played. The default
value is one, meaning the animation will play from beginning to end once.
A value of <span class=prop-value>‘<code
class=property>infinite</code>’</span> will cause the animation to
repeat forever. Non-integer numbers will cause the animation to end
part-way through a cycle. Negative values for <span
class=prop-name>‘<a href="#animation-iteration-count"><code
class=property>animation-iteration-count</code></a>’</span> are
treated as zero. This property is often used with an <span
class=prop-name>‘<a href="#animation-direction"><code
class=property>animation-direction</code></a>’</span> value of <span
class=prop-value>‘<code
class=property>alternate</code>’</span>, which will cause the
animation to play in reverse on alternate cycles.
<table class=propdef>
<tbody>
<tr>
<td> <em>Name:</em>
<td> <dfn id=animation-iteration-count>animation-iteration-count</dfn>
<tr>
<td> <em>Value:</em>
<td> infinite | <number> [, infinite | <number>]*
<tr>
<td> <em>Initial:</em>
<td> 1
<tr>
<td> <em>Applies to:</em>
<td> block-level and inline-level elements
<tr>
<td> <em>Inherited:</em>
<td> no
<tr>
<td> <em>Percentages:</em>
<td> N/A
<tr>
<td> <em>Media:</em>
<td> visual
<tr>
<td> <em>Computed value:</em>
<td> Same as specified value.
</table>
<!-- ======================================================================================================= -->
<h3 id=the-animation-direction-property-><span class=secno>3.6. </span> The
<span class=prop-name>‘<a href="#animation-direction"><code
class=property>animation-direction</code></a>’</span> Property</h3>
<p> The <span class=prop-name>‘<a href="#animation-direction"><code
class=property>animation-direction</code></a>’</span> property
defines whether or not the animation should play in reverse on alternate
cycles. If <span class=prop-value>‘<code
class=property>alternate</code>’</span> is specified, 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. When an animation is played in reverse the timing
functions are also reversed. For example, when played in reverse an
ease-in animation would appear to be an ease-out animation.
<table class=propdef>
<tbody>
<tr>
<td> <em>Name:</em>
<td> <dfn id=animation-direction>animation-direction</dfn>
<tr>
<td> <em>Value:</em>
<td> normal | alternate [, normal | alternate]*
<tr>
<td> <em>Initial:</em>
<td> normal
<tr>
<td> <em>Applies to:</em>
<td> block-level and inline-level elements
<tr>
<td> <em>Inherited:</em>
<td> no
<tr>
<td> <em>Percentages:</em>
<td> N/A
<tr>
<td> <em>Media:</em>
<td> visual
<tr>
<td> <em>Computed value:</em>
<td> Same as specified value.
</table>
<!-- ======================================================================================================= -->
<h3 id=the-animation-play-state-property-><span class=secno>3.7. </span>
The <span class=prop-name>‘<a href="#animation-play-state"><code
class=property>animation-play-state</code></a>’</span> Property</h3>
<p> The <span class=prop-name>‘<a href="#animation-play-state"><code
class=property>animation-play-state</code></a>’</span> property
defines whether the animation is running or paused. A running animation
can be paused by setting this property to <span
class=prop-value>‘<code class=property>paused</code>’</span>.
To continue running a paused animation this property can be set to <span
class=prop-value>‘<code class=property>running</code>’</span>.
A paused animation will continue to display the current value of the
animation in a static state, as if the time of the animation is constant.
When a paused animation is resumed, it restarts from the current value,
not necessarily from the beginning of the animation.
<table class=propdef>
<tbody>
<tr>
<td> <em>Name:</em>
<td> <dfn id=animation-play-state>animation-play-state</dfn>
<tr>
<td> <em>Value:</em>
<td> running | paused [, running | paused]*
<tr>
<td> <em>Initial:</em>
<td> running
<tr>
<td> <em>Applies to:</em>
<td> block-level and inline-level elements
<tr>
<td> <em>Inherited:</em>
<td> no
<tr>
<td> <em>Percentages:</em>
<td> N/A
<tr>
<td> <em>Media:</em>
<td> visual
<tr>
<td> <em>Computed value:</em>
<td> Same as specified value.
</table>
<!-- ======================================================================================================= -->
<h3 id=the-animation-delay-property-><span class=secno>3.8. </span> The
<span class=prop-name>‘<a href="#animation-delay"><code
class=property>animation-delay</code></a>’</span> Property</h3>
<p> The <span class=prop-name>‘<a href="#animation-delay"><code
class=property>animation-delay</code></a>’</span> property defines
when the animation will start. It allows an animation to begin execution
some time after it is applied. An <span class=prop-name>‘<a
href="#animation-delay"><code
class=property>animation-delay</code></a>’</span> value of
‘<code class=css>0</code>’ means the animation will execute as
soon as it is applied. Otherwise, the value specifies an offset from the
moment the animation is applied, and the animation will delay execution by
that offset.
<p> If the value for <span class=prop-name>‘<a
href="#animation-delay"><code
class=property>animation-delay</code></a>’</span> is a negative time
offset then the animation will execute the moment it is applied, but will
appear to have begun execution at the specified offset. That is, the
animation will appear to begin part-way through its play cycle. In the
case where an animation has implied starting values and a negative <span
class=prop-name>‘<a href="#animation-delay"><code
class=property>animation-delay</code></a>’</span>, the starting
values are taken from the moment the animation is applied.
<table class=propdef>
<tbody>
<tr>
<td> <em>Name:</em>
<td> <dfn id=animation-delay>animation-delay</dfn>
<tr>
<td> <em>Value:</em>
<td> <time> [, <time>]*
<tr>
<td> <em>Initial:</em>
<td> 0
<tr>
<td> <em>Applies to:</em>
<td> block-level and inline-level elements
<tr>
<td> <em>Inherited:</em>
<td> no
<tr>
<td> <em>Percentages:</em>
<td> N/A
<tr>
<td> <em>Media:</em>
<td> visual
<tr>
<td> <em>Computed value:</em>
<td> Same as specified value.
</table>
<!-- ======================================================================================================= -->
<h3 id=the-animation-fill-mode-property-><span class=secno>3.9. </span> The
<span class=prop-name>‘<a href="#animation-fill-mode"><code
class=property>animation-fill-mode</code></a>’</span> Property</h3>
<p> The <span class=prop-name>‘<a href="#animation-fill-mode"><code
class=property>animation-fill-mode</code></a>’</span> 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 <span class=prop-name>‘<a
href="#animation-name"><code
class=property>animation-name</code></a>’</span> property is set on
an element) and the time it begins execution (which is determined by the
<span class=prop-name>‘<a href="#animation-delay"><code
class=property>animation-delay</code></a>’</span> property). Also,
by default an animation does not affect property values after the
animation ends (determined by the <span class=prop-name>‘<a
href="#animation-duration"><code
class=property>animation-duration</code></a>’</span> property). The
value of <span class=prop-name>‘<a href="#animation-fill-mode"><code
class=property>animation-fill-mode</code></a>’</span> can override
this behavior.
<p> If the value for <span class=prop-name>‘<a
href="#animation-fill-mode"><code
class=property>animation-fill-mode</code></a>’</span> is <span
class=prop-value>‘<code