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This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for usage in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the specification changes.

Summary

The animation-fill-mode CSS property specifies how a CSS animation should apply styles to its target before and after it is executing.

Initial valuenone
Applies toall elements, ::before and ::after pseudo-elements
Inheritedno
Mediavisual
Computed valueas specified
Animatableno
Canonical orderthe unique non-ambiguous order defined by the formal grammar

Syntax

animation-fill-mode: none;
animation-fill-mode: forwards;
animation-fill-mode: backwards;
animation-fill-mode: both;

/* Several values may be given, separated by commas. */
/* Each applies for each animation in animation-name. */
animation-fill-mode: none, backwards;
animation-fill-mode: both, forwards, none;

Values

none
The animation will not apply any styles to the target before or after it is executing.
forwards
The target will retain the computed values set by the last keyframe encountered during execution. The last keyframe encountered depends on the value of animation-direction and animation-iteration-count:
animation-direction animation-iteration-count last keyframe encountered
normal even or odd 100% or to
reverse even or odd 0% or from
alternate even 0% or from
alternate odd 100% or to
alternate-reverse even 100% or to
alternate-reverse odd 0% or from
backwards
The animation will apply the values defined in the first relevant keyframe as soon as it is applied to the target, and retain this during the animation-delay period. The first relevant keyframe depends on the value of animation-direction:
animation-direction first relevant keyframe
normal or alternate 0% or from
reverse or alternate-reverse 100% or to
both
The animation will follow the rules for both forwards and backwards, thus extending the animation properties in both directions.

Formal syntax

<single-animation-fill-mode>#

where
<single-animation-fill-mode> = none | forwards | backwards | both

Example

You can see the effect of animation-fill-mode in the following example. For animations that run for an infinite time, you might want them to end on the last state rather than the first.

HTML content

<p>Move your mouse over the grey box</p>
<div class="demo">
  <div class="grows">This just grows</div>
  <div class="growsandstays">This grows and stays big</div>
</div>

CSS content

.demo {
  border-top: 100px solid #ccc;
  height: 300px;
  font-family: sans-serif;
}
@keyframes grow {
    0% { font-size: 0 }
    100% { font-size: 40px }
}
@-webkit-keyframes grow {
    0% { font-size: 0 }
    100% { font-size: 40px }
}
.demo:hover .grows {
    animation-name: grow;
    animation-duration: 3s;
    -webkit-animation-name: grow;
    -webkit-animation-duration: 3s;
}
.demo:hover .growsandstays {
    animation-name: grow;
    animation-duration: 3s;
    animation-fill-mode: forwards;
    -webkit-animation-name: grow;
    -webkit-animation-duration: 3s;
    -webkit-animation-fill-mode: forwards;
}

Specifications

Specification Status Comment
CSS Animations
The definition of 'animation-fill-mode' in that specification.
Working Draft Initial definition

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support (Yes)-webkit
43.0
5.0 (5.0)-moz
16.0 (16.0)[1]
10 12-o
12.10
4.0-webkit
Feature Android Chrome Firefox Mobile (Gecko) IE Phone Opera Mobile Safari Mobile Chrome for Android
Basic support ? ? ? ? ? ? ?

[1] In addition to the unprefixed support, Gecko 44.0 (Firefox 44.0 / Thunderbird 44.0 / SeaMonkey 2.41) added support for a -webkit prefixed version of the property for web compatibility reasons behind the preference layout.css.prefixes.webkit, defaulting to false. Since Gecko 49.0 (Firefox 49.0 / Thunderbird 49.0 / SeaMonkey 2.46) the preference defaults to true.

See also