animation - CSS: Cascading Style Sheets

The animation shorthand CSS property applies an animation between styles. It is a shorthand for animation-name, animation-duration, animation-timing-function, animation-delay, animation-iteration-count, animation-direction, animation-fill-mode, and animation-play-state.

/* @keyframes duration | timing-function | delay |
iteration-count | direction | fill-mode | play-state | name */
animation: 3s ease-in 1s 2 reverse both paused slidein;

/* @keyframes name | duration | timing-function | delay */
animation: 3s linear 1s slidein;

/* @keyframes name | duration */
animation: slidein 3s;

<div class="grid">
  <div class="col">
    <div class="note">
      Given the following animation:
      <pre>@keyframes slidein {
  from { transform: scaleX(0); }
  to   { transform: scaleX(1); }
}</pre>
    </div>
    <div class="row">
      <div class="cell">
        <button class="play" title="PLAY"></button>
      </div>
      <div class="cell flx">
        <div class="overlay">animation: 3s ease-in 1s 2 reverse both paused slidein;</div>
        <div class="animation a1"></div>
      </div>
    </div>
    <div class="row">
      <div class="cell">
        <button class="pause" title="PAUSE"></button>
      </div>
      <div class="cell flx">
        <div class="overlay">animation: 3s linear 1s slidein;</div>
        <div class="animation a2"></div>
      </div>
    </div>
    <div class="row">
      <div class="cell">
        <button class="pause" title="PAUSE"></button>
      </div>
      <div class="cell flx">
        <div class="overlay">animation: 3s slidein;</div>
        <div class="animation a3"></div>
      </div>
    </div>
  </div>
</div>

html,body {
  height: 100%;
  box-sizing: border-box;
}

pre { margin-bottom: 0; }
svg { width: 1.5em; height: 1.5em; }

button {
  width: 27px;
  height: 27px;
  background-size: 16px;
  background-position: center;
  background-repeat: no-repeat;
  border-radius: 3px;
  cursor: pointer;
}

button.play {
  background-image: url('data:image/svg+xml;charset=utf-8,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20viewBox%3D%220%200%2016%2016%22%3E%3Cstyle%3Epath%20%7Bdisplay%3Anone%7D%20path%3Atarget%7Bdisplay%3Ablock%7D%3C%2Fstyle%3E%3Cpath%20id%3D%22play%22%20d%3D%22M3%2C3%20L3%2C13%20L13%2C8%20Z%22%20%2F%3E%3Cpath%20id%3D%22pause%22%20d%3D%22M5%2C4%20L7%2C4%20L7%2C13%20L5%2C13%20Z%20M9%2C4%20L11%2C4%20L11%2C13%20L9%2C13%20Z%22%20%2F%3E%3Cpath%20id%3D%22restart%22%20d%3D%22M13%2C9%20A5%2C5%2C1%2C1%2C1%2C8%2C4%20L8%2C2%20L12%2C5%20L8%2C8%20L8%2C6%20A3%2C3%2C1%2C1%2C0%2C11%2C9%20A1%2C1%2C1%2C1%2C1%2C13%2C9%20z%22%20%2F%3E%3C%2Fsvg%3E#play');
}

button.pause {
  background-image: url('data:image/svg+xml;charset=utf-8,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20viewBox%3D%220%200%2016%2016%22%3E%3Cstyle%3Epath%20%7Bdisplay%3Anone%7D%20path%3Atarget%7Bdisplay%3Ablock%7D%3C%2Fstyle%3E%3Cpath%20id%3D%22play%22%20d%3D%22M3%2C3%20L3%2C13%20L13%2C8%20Z%22%20%2F%3E%3Cpath%20id%3D%22pause%22%20d%3D%22M5%2C4%20L7%2C4%20L7%2C13%20L5%2C13%20Z%20M9%2C4%20L11%2C4%20L11%2C13%20L9%2C13%20Z%22%20%2F%3E%3Cpath%20id%3D%22restart%22%20d%3D%22M13%2C9%20A5%2C5%2C1%2C1%2C1%2C8%2C4%20L8%2C2%20L12%2C5%20L8%2C8%20L8%2C6%20A3%2C3%2C1%2C1%2C0%2C11%2C9%20A1%2C1%2C1%2C1%2C1%2C13%2C9%20z%22%20%2F%3E%3C%2Fsvg%3E#pause');
}

button.restart {
  background-image: url('data:image/svg+xml;charset=utf-8,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20viewBox%3D%220%200%2016%2016%22%3E%3Cstyle%3Epath%20%7Bdisplay%3Anone%7D%20path%3Atarget%7Bdisplay%3Ablock%7D%3C%2Fstyle%3E%3Cpath%20id%3D%22play%22%20d%3D%22M3%2C3%20L3%2C13%20L13%2C8%20Z%22%20%2F%3E%3Cpath%20id%3D%22pause%22%20d%3D%22M5%2C4%20L7%2C4%20L7%2C13%20L5%2C13%20Z%20M9%2C4%20L11%2C4%20L11%2C13%20L9%2C13%20Z%22%20%2F%3E%3Cpath%20id%3D%22restart%22%20d%3D%22M13%2C9%20A5%2C5%2C1%2C1%2C1%2C8%2C4%20L8%2C2%20L12%2C5%20L8%2C8%20L8%2C6%20A3%2C3%2C1%2C1%2C0%2C11%2C9%20A1%2C1%2C1%2C1%2C1%2C13%2C9%20z%22%20%2F%3E%3C%2Fsvg%3E#restart');
}

.grid {
  width: 100%;
  height: 100%;
  display: flex;
  background: #EEE;
  font: 1em monospace;
}

.row {
  display: flex;
  flex: 1 auto;
  flex-direction: row;
  flex-wrap: wrap;
  justify-content: space-between;
}

.col {
  display: flex;
  flex: 1 auto;
  flex-direction: column;
}

.cell {
  box-sizing: border-box;
  margin: .5em;
  padding: 0;
  background-color: #FFF;
  overflow: hidden;
  text-align: left;
}

.flx {
  flex: 1 0;
}

.note {
  background: #fff3d4;
  padding: 1em;
  margin: .5em;
  font: .8em sans-serif;
  text-align: left;
  flex: none;
}

.overlay { padding: .5em; }

@keyframes slidein {
  from { transform: scaleX(0); }
  to { transform: scaleX(1); }
}

.a1 { animation: 3s ease-in 1s 2 reverse both paused slidein; }
.a2 { animation: 3s linear 1s slidein; }
.a3 { animation: 3s slidein; }

.animation {
  background: #3F87A6;
  width: 100%;
  height: calc(100% - 1.5em);
  transform-origin: left center;
}

window.addEventListener('load', function () {
  var ANIMATION = Array.from(document.querySelectorAll('.animation'));
  var BUTTON    = Array.from(document.querySelectorAll('button'));

  function toggleButton (btn, type) {
    btn.classList.remove('play', 'pause', 'restart');
    btn.classList.add(type);
    btn.title = type.toUpperCase(type);
  }

  function playPause (i) {
    var btn  = BUTTON[i];
    var anim = ANIMATION[i];

    if (btn.classList.contains('play')) {
      anim.style.animationPlayState = 'running';
      toggleButton(btn, 'pause');
    } else if (btn.classList.contains('pause')) {
      anim.style.animationPlayState = 'paused';
      toggleButton(btn, 'play');
    } else {
      anim.classList.remove('a' + (i + 1));
      setTimeout(function () {
        toggleButton(btn, i === 0 ? 'play' : 'pause');
        anim.style.animationPlayState = '';
        anim.classList.add('a' + (i + 1));
      }, 100)
    }
  }

  ANIMATION.forEach(function (node, index) {
    node.addEventListener('animationstart', function () { toggleButton(BUTTON[index], 'pause');   });
    node.addEventListener('animationend',   function () { toggleButton(BUTTON[index], 'restart'); });
  });

  BUTTON.forEach(function (btn, index) {
    btn.addEventListener('click', function () { playPause(index); });
  });
})

A description of which properties are animatable is available; it's worth noting that this description is also valid for CSS transitions.

Constituent properties

This property is a shorthand for the following CSS properties:

Syntax

The animation property is specified as one or more single animations, separated by commas.

Each individual animation is specified as:

zero or one occurrences of the following values:
an optional name for the animation, which may be none, a <custom-ident>, or a <string>
zero, one, or two <time> values

The order of values within each animation definition is important: the first value that can be parsed as a <time> is assigned to the animation-duration, and the second one is assigned to animation-delay.

The order within each animation definition is also important for distinguishing animation-name values from other keywords. When parsed, keywords that are valid for properties other than animation-name, and whose values were not found earlier in the shorthand, must be accepted for those properties rather than for animation-name. Furthermore, when serialized, default values of other properties must be output in at least the cases necessary to distinguish an animation-name that could be a value of another property, and may be output in additional cases.

Values

<single-animation-iteration-count>: The number of times the animation is played. The value must be one of those available in animation-iteration-count.
<single-animation-direction>: The direction in which the animation is played. The value must be one of those available in animation-direction.
<single-animation-fill-mode>: Determines how styles should be applied to the animation's target before and after its execution. The value must be one of those available in animation-fill-mode.
<single-animation-play-state>: Determines whether the animation is playing or not. The value must be one of those available in animation-play-state.

Accessibility concerns

Blinking and flashing animation can be problematic for people with cognitive concerns such as Attention Deficit Hyperactivity Disorder (ADHD). Additionally, certain kinds of motion can be a trigger for Vestibular disorders, epilepsy, and migraine and Scotopic sensitivity.

Consider providing a mechanism for pausing or disabling animation, as well as using the Reduced Motion Media Query to create a complimentary experience for users who have expressed a preference for no animated experiences.

Formal definition

Initial value	as each of the properties of the shorthand: `animation-name`: `none` `animation-duration`: `0s` `animation-timing-function`: `ease` `animation-delay`: `0s` `animation-iteration-count`: `1` `animation-direction`: `normal` `animation-fill-mode`: `none` `animation-play-state`: `running`
Applies to	all elements, `::before` and `::after` pseudo-elements
Inherited	no
Computed value	as each of the properties of the shorthand: `animation-name`: as specified `animation-duration`: as specified `animation-timing-function`: as specified `animation-delay`: as specified `animation-direction`: as specified `animation-iteration-count`: as specified `animation-fill-mode`: as specified `animation-play-state`: as specified
Animation type	discrete

Formal syntax

<single-animation>#where 
<single-animation> = <time> | <timing-function> | <time> | <single-animation-iteration-count> | <single-animation-direction> | <single-animation-fill-mode> | <single-animation-play-state> | [ none | <keyframes-name> ]
where 
<timing-function> = linear | <cubic-bezier-timing-function> | <step-timing-function>
<single-animation-iteration-count> = infinite | <number>
<single-animation-direction> = normal | reverse | alternate | alternate-reverse
<single-animation-fill-mode> = none | forwards | backwards | both
<single-animation-play-state> = running | paused
<keyframes-name> = <custom-ident> | <string>
where 
<cubic-bezier-timing-function> = ease | ease-in | ease-out | ease-in-out | cubic-bezier(<number <a href="/docs/CSS/Value_definition_syntax#Brackets" title="Brackets: enclose several entities, combinators, and multipliers to transform them as a single component">[0,1]>, <number>, <number <a href="/docs/CSS/Value_definition_syntax#Brackets" title="Brackets: enclose several entities, combinators, and multipliers to transform them as a single component">[0,1]>, <number>)
<step-timing-function> = step-start | step-end | steps(<integer>[, <step-position>]?)
where 
<step-position> = jump-start | jump-end | jump-none | jump-both | start | end

Examples

Cylon Eye

<div class="view_port">
  <div class="polling_message">
    Listening for dispatches
  </div>
  <div class="cylon_eye"></div>
</div>

.polling_message {
  color: white;
  float: left;
  margin-right: 2%;
}

.view_port {
  background-color: black;
  height: 25px;
  width: 100%;
  overflow: hidden;
}

.cylon_eye {
  background-color: red;
  background-image: linear-gradient(to right,
      rgba(0, 0, 0, .9) 25%,
      rgba(0, 0, 0, .1) 50%,
      rgba(0, 0, 0, .9) 75%);
  color: white;
  height: 100%;
  width: 20%;

  -webkit-animation: 4s linear 0s infinite alternate move_eye;
          animation: 4s linear 0s infinite alternate move_eye;
}

@-webkit-keyframes move_eye { from { margin-left: -20%; } to { margin-left: 100%; }  }
        @keyframes move_eye { from { margin-left: -20%; } to { margin-left: 100%; }  }

See Using CSS animations for additional examples.

Specifications

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

Browser compatibility

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`animation`	Chrome Full support 43 Full support 43 Full support 3 Prefixed Prefixed Implemented with the vendor prefix: -webkit-	Edge Full support 12 Full support 12 Full support 12 Prefixed Prefixed Implemented with the vendor prefix: -webkit-	Firefox Full support 16 Full support 16 Full support 49 Prefixed Prefixed Implemented with the vendor prefix: -webkit- Full support 44 Prefixed Disabled Prefixed Implemented with 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. Full support 5 Prefixed Prefixed Implemented with the vendor prefix: -moz-	IE Full support 10	Opera Full support 30 Full support 30 Full support 15 Prefixed Prefixed Implemented with the vendor prefix: -webkit- No support 12.1 — 15 No support 12 — 15 Prefixed Prefixed Implemented with the vendor prefix: -o-	Safari Full support 9 Full support 9 Full support 4 Prefixed Prefixed Implemented with the vendor prefix: -webkit-	WebView Android Full support 43 Full support 43 Full support 2 Prefixed Notes Prefixed Implemented with the vendor prefix: -webkit- Notes The `animation-fill-mode` property is not supported in Android browsers below 2.3.	Chrome Android Full support 43 Full support 43 Full support 18 Prefixed Prefixed Implemented with the vendor prefix: -webkit-	Firefox Android Full support 16 Full support 16 Full support 49 Prefixed Prefixed Implemented with the vendor prefix: -webkit- Full support 44 Prefixed Disabled Prefixed Implemented with 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. Full support 5 Prefixed Prefixed Implemented with the vendor prefix: -moz-	Opera Android Full support 30 Full support 30 Full support 14 Prefixed Prefixed Implemented with the vendor prefix: -webkit- No support 12.1 — 14 No support 12 — 14 Prefixed Prefixed Implemented with the vendor prefix: -o-	Safari iOS Full support 9 Full support 9 Full support 3.2 Prefixed Prefixed Implemented with the vendor prefix: -webkit-	Samsung Internet Android Full support 4.0 Full support 4.0 Full support 1.0 Prefixed Prefixed Implemented with the vendor prefix: -webkit-

Legend

Full support: Full support
See implementation notes.: See implementation notes.
User must explicitly enable this feature.: User must explicitly enable this feature.
Requires a vendor prefix or different name for use.: Requires a vendor prefix or different name for use.

Quantum CSS notes

Gecko has a bug whereby when you animate an offscreen element onscreen but specify a delay, Gecko does not repaint on some platforms, e.g. Windows (bug 1383239). This has been fixed in Firefox's new parallel CSS engine (also known as Quantum CSS or Stylo, planned for release in Firefox 57).
Another Gecko bug means that <details> elements can't be made open by default using the open attribute if they have an animation active on them (bug 1382124). Quantum CSS fixes this.
A further bug means that animations using em units are not affected by changes to the font-size on the animated element's parent, whereas they should be (bug 1254424). Quantum CSS fixes this.