Web/API/Web Animations API/Keyframe Formats

This is an experimental technologyCheck the Browser compatibility table carefully before using this in production.

Element.animate(), KeyframeEffect.KeyframeEffect(), and KeyframeEffect.setKeyframes() all accept objects formatted to represent a set of keyframes. There are several options to this format, which are explained below.

Syntax

There are two different ways to format keyframes:

An array of objects (keyframes) consisting of properties and values to iterate over. This is the canonical format returned by the getKeyframes() method.
```
element.animate([ 
  { // from
    opacity: 0,
    color: "#fff"
  }, 
  { // to
    opacity: 1,
    color: "#000"
  }
], 2000);
```
Offsets for each keyframe can be specified by providing an offset value.
```
element.animate([ { opacity: 1 },
                  { opacity: 0.1, offset: 0.7 },
                  { opacity: 0 } ],
                2000);
```
Note: offset values, if provided, must be between 0.0 and 1.0 (inclusive) and arranged in ascending order.

It is not necessary to specify an offset for every keyframe. Keyframes without a specified offset will be evenly spaced between adjacent keyframes.

The easing to apply between keyframes can be specified by providing an easing value as illustrated below.
```
element.animate([ { opacity: 1, easing: 'ease-out' },
                  { opacity: 0.1, easing: 'ease-in' },
                  { opacity: 0 } ],
                2000);
```
In this example, the specified easing only applies from the keyframe where it is specified until the next keyframe. Any easing value specified on the options argument, however, applies across a single iteration of the animation — for the entire duration.
An object containing key-value pairs consisting of the property to animate and an array of values to iterate over.
```
element.animate({
  opacity: [ 0, 1 ],          // [ from, to ]
  color:   [ "#fff", "#000" ] // [ from, to ]
}, 2000);
```
Using this format, the number of elements in each array does not need to be equal. The provided values will be spaced out independently.
```
element.animate({
  opacity: [ 0, 1 ], // offset: 0, 1
  backgroundColor: [ "red", "yellow", "green" ], // offset: 0, 0.5, 1
}, 2000);
```
The special keys offset, easing, and composite (described below) may be specified alongside the property values.
```
element.animate({
  opacity: [ 0, 0.9, 1 ],
  offset: [ 0, 0.8 ], // Shorthand for [ 0, 0.8, 1 ]
  easing: [ 'ease-in', 'ease-out' ],
}, 2000);
```
After generating a suitable set of keyframes from the property value lists, each supplied offset is applied to the corresponding keyframe. If there are insufficient values, or if the list contains null values, the keyframes without specified offsets will be evenly spaced as with the array format described above.

If there are too few easing or composite values, the corresponding list will be repeated as needed.

Implicit to/from keyframes

In newer browser versions, you are able to set a beginning or end state for an animation only (i.e. a single keyframe), and the browser will infer the other end of the animation if it is able to. For example, consider [[../../../../../../../mdn.github.io/dom-examples/web-animations-api/implicit-keyframes|this simple animation]] — the Keyframe object looks like so:

let rotate360 = [
  { transform: 'rotate(360deg)' }
];

We have only specified the end state of the animation, and the beginning state is implied.

Attributes

Keyframes may specify property-value pairs for any of the animatable css properties. The property names are specified using camel-case so for example background-color becomes backgroundColor and background-position-x becomes backgroundPositionX. Shorthand values such as margin are also permitted.

Two exceptional CSS properties are:

float, which must be written as cssFloat since "float" is a reserved word in JavaScript. It's just for reference here, this will have no effect on animation since "float" is not an animatable CSS property.
offset, which must be written as cssOffset since "offset" represents the keyframe offset as described below.

The following special attributes may also be specified:

offset: The offset of the keyframe specified as a number between 0.0 and 1.0 inclusive or null. This is equivalent to specifying start and end states in percentages in CSS stylesheets using @keyframes. If this value is null or missing, the keyframe will be evenly spaced between adjacent keyframes.
easing: The timing function used from this keyframe until the next keyframe in the series.
composite: The KeyframeEffect.composite operation used to combine the values specified in this keyframe with the underlying value. This will be auto if the composite operation specified on the effect is being used.

Specifications

Specification	Status	Comment
Web AnimationsThe definition of 'Keyframe object formats' in that specification.	Working Draft	Initial definition

Browser compatibility

`Element.animate`

Update compatibility data on GitHub

	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
`animate` Experimental'	Chrome Full support 36	Edge Full support 79	Firefox Full support 48	IE No support No	Opera Full support 23	Safari Full support 13.1 Full support 13.1 Full support Yes Disabled' Disabled' This feature is behind the `Web Animations` preference and the `CSS Animations via Web Animations` preference.	WebView Android Full support 37	Chrome Android Full support 36	Firefox Android Full support 48	Opera Android Full support 24	Safari iOS Full support 13.4	Samsung Internet Android Full support 3.0
`composite` option Experimental'	Chrome Full support 79 Disabled' Full support 79 Disabled' Disabled' From version 79: this feature is behind the `Experimental Web Platform Features` preference. To change preferences in Chrome, visit chrome://flags.	Edge Full support 79 Disabled' Full support 79 Disabled' Disabled' From version 79: this feature is behind the `Experimental Web Platform Features` preference.	Firefox Full support 80 Full support 80 No support 63 — 79 Disabled' Disabled' From version 63 until version 79 (exclusive): this feature is behind the `dom.animations-api.compositing.enabled` preference. To change preferences in Firefox, visit about:config. No support 53 — 63 Disabled' Disabled' From version 53 until version 63 (exclusive): this feature is behind the `dom.animations-api.core.enabled` preference. To change preferences in Firefox, visit about:config.	IE No support No	Opera Full support 66 Disabled' Full support 66 Disabled' Disabled' From version 66: this feature is behind the `Experimental Web Platform Features` preference.	Safari No support No	WebView Android No support No	Chrome Android Full support 79 Disabled' Full support 79 Disabled' Disabled' From version 79: this feature is behind the `Experimental Web Platform Features` preference. To change preferences in Chrome, visit chrome://flags.	Firefox Android Full support 63 Disabled' Full support 63 Disabled' Disabled' From version 63: this feature is behind the `dom.animations-api.compositing.enabled` preference. To change preferences in Firefox, visit about:config. No support 53 — 63 Disabled' Disabled' From version 53 until version 63 (exclusive): this feature is behind the `dom.animations-api.core.enabled` preference. To change preferences in Firefox, visit about:config.	Opera Android No support No	Safari iOS No support No	Samsung Internet Android No support No
`id` option Experimental'	Chrome Full support 50	Edge Full support 79	Firefox Full support 48	IE No support No	Opera Full support 37	Safari No support No	WebView Android Full support 50	Chrome Android Full support 50	Firefox Android Full support 48	Opera Android Full support 37	Safari iOS No support No	Samsung Internet Android Full support 5.0
Implicit to/from keyframes are supported Experimental'	Chrome No support No Notes' No support No Notes' Notes' Currently Chrome Canary only	Edge No support No	Firefox Full support 75	IE No support No	Opera No support No	Safari Partial support 13.1 Notes' Partial support 13.1 Notes' Notes' Implementation seems somewhat buggy. More information will follow when available.	WebView Android No support No	Chrome Android No support No Notes' No support No Notes' Notes' Currently Chrome Canary only	Firefox Android No support No	Opera Android No support No	Safari iOS Partial support 13.4 Notes' Partial support 13.4 Notes' Notes' Implementation seems somewhat buggy. More information will follow when available.	Samsung Internet Android No support No
`iterationComposite` option Experimental'	Chrome No support No	Edge No support No	Firefox Full support 80 Full support 80 No support 63 — 79 Disabled' Disabled' From version 63 until version 79 (exclusive): this feature is behind the `dom.animations-api.compositing.enabled` preference. To change preferences in Firefox, visit about:config. No support 51 — 63 Disabled' Disabled' From version 51 until version 63 (exclusive): this feature is behind the `dom.animations-api.core.enabled` preference. To change preferences in Firefox, visit about:config.	IE No support No	Opera No support No	Safari No support No	WebView Android No support No	Chrome Android No support No	Firefox Android Full support 63 Disabled' Full support 63 Disabled' Disabled' From version 63: this feature is behind the `dom.animations-api.compositing.enabled` preference. To change preferences in Firefox, visit about:config. No support 51 — 63 Disabled' Disabled' From version 51 until version 63 (exclusive): this feature is behind the `dom.animations-api.core.enabled` preference. To change preferences in Firefox, visit about:config.	Opera Android No support No	Safari iOS No support No	Samsung Internet Android No support No
`pseudoElement` option Experimental'	Chrome Partial support 81 Notes' Disabled' Partial support 81 Notes' Disabled' Notes' A valid animation object is returned but the targeted pseudoelement is not visually animated. Disabled' From version 81: this feature is behind the `Experimental Web Platform Features` preference. To change preferences in Chrome, visit chrome://flags.	Edge Partial support 81 Notes' Disabled' Partial support 81 Notes' Disabled' Notes' A valid animation object is returned but the targeted pseudoelement is not visually animated. Disabled' From version 81: this feature is behind the `Experimental Web Platform Features` preference.	Firefox Full support 75	IE No support No	Opera Partial support 68 Notes' Disabled' Partial support 68 Notes' Disabled' Notes' A valid animation object is returned but the targeted pseudoelement is not visually animated. Disabled' From version 68: this feature is behind the `Experimental Web Platform Features` preference.	Safari No support No	WebView Android No support No	Chrome Android Partial support 81 Notes' Disabled' Partial support 81 Notes' Disabled' Notes' A valid animation object is returned but the targeted pseudoelement is not visually animated. Disabled' From version 81: this feature is behind the `Experimental Web Platform Features` preference. To change preferences in Chrome, visit chrome://flags.	Firefox Android No support No	Opera Android No support No	Safari iOS No support No	Samsung Internet Android No support No

Legend

Full support: Full support
Partial support: Partial support
No support: No support
Experimental. Expect behavior to change in the future.': Experimental. Expect behavior to change in the future.
See implementation notes.': See implementation notes.
User must explicitly enable this feature.': User must explicitly enable this feature.