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@keyframes

The @keyframes CSS at-rule controls the intermediate steps in a CSS animation sequence by defining styles for keyframes (or waypoints) along the animation sequence. This gives more control over the intermediate steps of the animation sequence than transitions.

@keyframes slidein {
  from {
    margin-left: 100%;
    width: 300%;
  }

  to {
    margin-left: 0%;
    width: 100%;
  }
}

JavaScript can access the @keyframes at-rule with the CSS object model interface CSSKeyframesRule.

To use keyframes, create a @keyframes rule with a name that is then used by the animation-name property to match an animation to its keyframe declaration. Each @keyframes rule contains a style list of keyframe selectors, which specify percentages along the animation when the keyframe occurs, and a block containing the styles for that keyframe.

You can list the keyframe percentages in any order; they will be handled in the order they should occur.

Valid keyframe lists

If a keyframe rule doesn't specify the start or end states of the animation (that is, 0%/from and 100%/to, browsers will use the element's existing styles for the start/end states. This can be used to animate an element from its initial state and back.

Properties that can't be animated in keyframe rules are ignored, but supported properties will still be animated.

Resolving duplicates

If multiple keyframe sets exist for a given name, the last one encountered by the parser is used. @keyframes rules don't cascade, so animations never derive keyframes from more than one rule set.

If a given animation time offset is duplicated, the last keyframe in the @keyframes rule for that percentage is used for that frame. There's no cascading within a @keyframes rule if multiple keyframes specify the same percentage values.

When properties are left out of some keyframes

Properties that aren't specified in every keyframe are interpolated if possible — properties that can't be interpolated are dropped from the animation. For example:

@keyframes identifier {
  0% { top: 0; left: 0; }
  30% { top: 50px; }
  68%, 72% { left: 50px; }
  100% { top: 100px; left: 100%; }
}

Here, the top property animates using the 0%, 30%, and 100% keyframes, and left animates using the 0%, 68%, and 100% keyframes.

When a keyframe is defined multiple times

If a keyframe is defined multiple times but not all affected properties are in each keyframe, only the values specified in the latest keyframe are considered. For example:

@keyframes identifier {
  0% { top: 0; }
  50% { top: 30px; left: 20px; }
  50% { top: 10px; }
  100% { top: 0; }
}

In this example, at the 50% keyframe, the value used is top: 10px and all other values at this keyframe are ignored.

Cascading keyframes are supported starting in Firefox 14. For the example above, it means that at the 50% keyframe, the value left: 20px will be considered. This is not defined in the specification yet, but it is being discussed.

!important in a keyframe

Declarations in a keyframe qualified with !important are ignored.

@keyframes important1 {
  from { margin-top: 50px; }
  50%  { margin-top: 150px !important; } /* ignored */
  to   { margin-top: 100px; }
}

@keyframes important2 {
  from { margin-top: 50px;
         margin-bottom: 100px; }
  to   { margin-top: 150px !important; /* ignored */
         margin-bottom: 50px; }
}

Syntax

Values

<custom-ident>
A name identifying the keyframe list. This must match the identifier production in CSS syntax.
from
A starting offset of 0%.
to
An ending offset of 100%.
<percentage>
A percentage of the time through the animation sequence at which the specified keyframe should occur.

Formal syntax

@keyframes <keyframes-name> {
  <keyframe-block-list>
}

where
<keyframes-name> = <custom-ident> | <string>
<keyframe-block-list> = <keyframe-block>+

where
<keyframe-block> = <keyframe-selector># { <declaration-list> }

where
<keyframe-selector> = from | to | <percentage>

Examples

See Using CSS animations for examples.

Specifications

Specification Status Comment
CSS Animations
The definition of '@keyframes' in that specification.
Working Draft

Browser compatibilityUpdate compatibility data on GitHub

Desktop
Chrome Edge Firefox Internet Explorer Opera Safari
Basic support 43
43
Yes
Prefixed
Prefixed Requires the vendor prefix: -webkit-
Yes 16
16
@keyframes is unsupported in scoped stylesheets in Firefox (bug 830056).
49
Prefixed
Prefixed Requires the vendor prefix: -webkit-
44
Prefixed Disabled
Prefixed Requires the vendor prefix: -webkit-
Disabled From version 44: this feature is behind the layout.css.prefixes.webkit preference (needs to be set to true). To change preferences in Firefox, visit about:config.
5
Prefixed
Prefixed Requires the vendor prefix: -moz-
10 12.1 — 15
12.1 — 15
15
Prefixed
Prefixed Requires the vendor prefix: -webkit-
12 — 15
Prefixed
Prefixed Requires the vendor prefix: -o-
9
9
4
Prefixed
Prefixed Requires the vendor prefix: -webkit-
Ignore !important declarations ? ? 19 ? ? ?
Mobile
Android webview Chrome for Android Edge Mobile Firefox for Android Opera for Android iOS Safari Samsung Internet
Basic support 43
43
Yes
Prefixed
Prefixed Requires the vendor prefix: -webkit-
43
43
Yes
Prefixed
Prefixed Requires the vendor prefix: -webkit-
Yes 16
16
49
Prefixed
Prefixed Requires the vendor prefix: -webkit-
44
Prefixed Disabled
Prefixed Requires the vendor prefix: -webkit-
Disabled From version 44: this feature is behind the layout.css.prefixes.webkit preference (needs to be set to true). To change preferences in Firefox, visit about:config.
5
Prefixed
Prefixed Requires the vendor prefix: -moz-
12.1
12.1
15
Prefixed
Prefixed Requires the vendor prefix: -webkit-
12 — 14
Prefixed
Prefixed Requires the vendor prefix: -o-
Yes
Yes
Yes
Prefixed
Prefixed Requires the vendor prefix: -webkit-
4.0
4.0
Yes
Prefixed
Prefixed Requires the vendor prefix: -webkit-
Ignore !important declarations ? ? ? 19 ? ? ?

Notes

  1. @keyframes unsupported in scoped stylesheets in Firefox (bug 830056).

See also

© 2005–2018 Mozilla Developer Network and individual contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/CSS/@keyframes