This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for usage in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the specification changes.

The easing property of the AnimationEffectTimingReadOnly object represents the timing function used to scale the time to produce easing effects. Easing is the rate of the animation's change over time.

Note: In AnimationEffectTiming, a mutable subclass of AnimationEffectTimingReadOnly used withKeyframeEffects, the property acts as both a getter and a setter.


// Getting the easing of the animation
var animationEasing = animation.effect.timing.easing;

// Setting the easing of the animation
animation.effect.timing.direction = "linear";


Accepts several pre-defined DOMString values, a steps() timing function like steps(5, end), or a custom cubic-bezier value like cubic-bezier(0.42, 0, 0.58, 1). Defaults to linear. Available values include:

A constant rate of change, neither accelerating nor deccelerating. 
cubic-bezier(<number>, <number>, <number>, <number>)
A diagram showing the points of a cubic bezier timing function.
Specifies a cubic Bézier timing function. The four numbers specify points P1 and P2 of the curve as (x1, y1, x2, y2). Both x values must be in the range [0, 1] or the definition is invalid.
A decelerated rate of change, going from fast to slow. Equivalent to cubic-bezier(0.25, 0.1, 0.25, 1).
An accelerated rate of change, going from slow to fast. Equivalent to cubic-bezier(0.42, 0, 1, 1).
Another decelerated rate of change, going from fast to slow. Equivalent to cubic-bezier(0, 0, 0.58, 1).
This rate of change speeds up in the middle. Equivalent to cubic-bezier(0.42, 0, 0.58, 1).
steps(<integer>[, [ start | end ] ]?)
A diagram of the various steps timing functions.
Specifies a step timing function. The first parameter specifies the number of intervals in the function. It must be a positive integer (greater than 0). The second parameter, which is optional, specifies the point at which the change of values occur within the interval. If the second parameter is omitted, it is given the value end.
Equivalent to steps(1, start)
Equivalent to steps(1, end).


In the Red Queen's Race example, we can inspect the Red Queen and Alice's animation to discover the secret to their sprite animation:

// Returns "steps(7, end)"
return redQueen_alice.effect.timing.easing;


Specification Status Comment
Web Animations
The definition of 'AnimationEffectTimingReadOnly.easing' in that specification.
Working Draft Editor's draft.

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support (Yes) 48 (48) No support (Yes) No support
Feature Android Android Webview Chrome for Android Firefox Mobile (Gecko) Firefox OS IE Mobile Opera Mobile Safari Mobile
Basic support ? ? ? ? ? No support No support No support

See also


© 2016 Mozilla Contributors
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.

Animation AnimationEffectTimingReadOnly API easing Experimental Property Reference web animations api