animation-fill-mode

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

Initial value	none
Applies to	all elements, ::before and ::after pseudo-elements
Inherited	no
Media	visual
Computed value	as specified
Animation type	discrete
Canonical order	the 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 when it's not executing; it will instead be displayed using its state based on all other CSS rules applied to it.

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. It demonstrates how, for an animation that runs for an infinite time, you can cause it to remain in its final state rather than reverting to the original state (which is the default).

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

[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

• Using CSS animations
• AnimationEvent