Web Animations API

Concepts and usage

The Web Animations API provides a common language for browsers and developers to describe animations on DOM elements. To get more information on the concepts behind the API and how to use it, read Using the Web Animations API.

Web Animations interfaces

Animation

Provides playback controls and a timeline for an animation node or source. Can take an object created with the KeyframeEffect() constructor.

KeyframeEffect

Describes sets of animatable properties and values, called keyframes and their timing options. These can then be played using the Animation() constructor.

AnimationTimeline

Represents the timeline of animation. This interface exists to define timeline features (inherited by DocumentTimeline and future timeline objects) and is not itself accessed by developers.

DocumentTimeline

Represents animation timelines, including the default document timeline (accessed using the Document.timeline property).

AnimationEffectTiming

An object containing timing properties returned by the timing attribute of a KeyframeEffect. It inherits its properties from AnimationEffectTimingReadOnly, but in a non-read only form.

SharedKeyframeList

Represents a sequence of keyframes that can be shared between KeyframeEffect objects. By using SharedKeyframeList objects, multiple KeyframeEffect objects can re-use the same keyframes without paying the cost of parsing them multiple times.

AnimationEffectTimingProperties

Element.animate(), KeyframeEffectReadOnly.KeyframeEffectReadOnly(), and KeyframeEffect.KeyframeEffect() all accept an optional dictionary object of timing properties.

Extensions to other interfaces

The Web Animations API adds some new features to document and element.

Extensions to the Document interface

document.timeline

The DocumentTimeline object representing the default document timeline.

document.getAnimations()

Returns an Array of Animation objects currently in effect on elements in the document.

Extensions to the Element interface

Element.animate()

A shortcut method for creating and playing an animation on an element. It returns the created Animation object instance.

Web Animations read-only interfaces

The following interfaces are included in the spec for purposes such as defining features used in multiple other places, or to serve as bases for multiple interfaces which can all be used as values of the same properties. You wouldn't directly use these in web development work, but they may be interesting for library authors to understand how the technology works so their implementations can be more effective, or for browser engineers looking for an easier reference than the spec provides.

AnimationEffectTimingReadOnly

A dictionary object of timing properties, which are inherited by the mutable AnimationEffectTiming interface associated with KeyframeEffect.

AnimationEffectReadOnly

Defines current and future "Animation Effects" like KeyframeEffect, which can be passed to Animation objects for playing, and KeyframeEffectReadOnly which is used by KeyframeEffect (inherited by CSS Animations and Transitions). All values of Animation.effect are of types based on AnimationEffectReadOnly.

KeyframeEffectReadOnly

Describes sets of animatable properties and values that can be played using the Animation() constructor, and which are inherited by KeyframeEffect.

Specifications

Specification	Status	Comment
Web Animations	Working Draft	Initial definition

Browser compatibility

[1] Only enabled in Firefox 52 Nightly and Dev edition. Turned off in Beta/release.

See also

• Using the Web Animations API
• Web Animations demos
• Polyfill
• Firefox's current implementation: AreWeAnimatedYet

• Browser support test