animation-fill-mode - CSS: Cascading Style Sheets 编辑

The animation-fill-mode CSS property sets how a CSS animation applies styles to its target before and after its execution.

The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone https://github.com/mdn/interactive-examples and send us a pull request.

It is often convenient to use the shorthand property animation to set all animation properties at once.

Syntax

/* Single animation */
animation-fill-mode: none;
animation-fill-mode: forwards;
animation-fill-mode: backwards;
animation-fill-mode: both;

/* Multiple animations */
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. The element will instead be displayed using any other CSS rules applied to it. This is the default value.

forwards

The target will retain the computed values set by the last keyframe encountered during execution. The last keyframe 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.

Note: When you specify multiple comma-separated values on an animation-* property, they will be assigned to the animations specified in the animation-name property in different ways depending on how many there are. For more information, see Setting multiple animation property values.

Formal definition

Formal syntax

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

Examples

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

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

CSS

.demo {
  border-top: 100px solid #ccc;
  height: 300px;
}

@keyframes grow {
  0% { font-size: 0; }
  100% { font-size: 40px; }
}

.demo:hover .grows {
  animation-name: grow;
  animation-duration: 3s;
}

.demo:hover .growsandstays {
  animation-name: grow;
  animation-duration: 3s;
  animation-fill-mode: forwards;
}

See CSS animations for more examples.

Specifications

Browser compatibility

BCD tables only load in the browser

See also

• Using CSS animations
• JavaScript AnimationEvent API