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

The EffectTiming dictionary, part of the Web Animations API, is used by Element.animate(), KeyframeEffectReadOnly(), and KeyframeEffect() to describe timing properties for animation effects. These properties are all optional, although without setting a duration the animation will not play.

Simply put, these properties describe how the user agent should go about making the transition from from keyframe to keyframe, and how to behave when the animation begins and ends.


delay Optional
The number of milliseconds to delay the start of the animation. Defaults to 0.
direction Optional
Whether the animation runs forwards (normal), backwards (reverse), switches direction after each iteration (alternate), or runs backwards and switches direction after each iteration (alternate-reverse). Defaults to "normal".
duration Optional
The number of milliseconds each iteration of the animation takes to complete. Defaults to 0. Although this is technically optional, keep in mind that your animation will not run if this value is 0.
easing Optional
The rate of the animation's change over time. Accepts the pre-defined values "linear", "ease", "ease-in", "ease-out", and "ease-in-out", or a custom "cubic-bezier" value like "cubic-bezier(0.42, 0, 0.58, 1)". Defaults to "linear".
endDelay Optional
The number of milliseconds to delay after the end of an animation. This is primarily of use when sequencing animations based on the end time of another animation. Defaults to 0. 
fill Optional
Dictates whether the animation's effects should be reflected by the element(s) prior to playing ("backwards"), retained after the animation has completed playing ("forwards"), or both. Defaults to "none".
iterationStart Optional
Describes at what point in the iteration the animation should start. 0.5 would indicate starting halfway through the first iteration for example, and with this value set, an animation with 2 iterations would end halfway through a third iteration. Defaults to 0.0.
iterations Optional
The number of times the animation should repeat. Defaults to 1, and can also take a value of Infinity to make it repeat for as long as the element exists.


Specification Status Comment
Web Animations
The definition of 'EffectTiming' in that specification.
Working Draft Initial definition

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support ? ?63 ? ? ?
delay Yes ?63 No Yes No
direction Yes ?63 No Yes No
duration Yes ?63 No Yes No
easing Yes ?63 No Yes No
endDelay Yes ?63 No Yes No
fill Yes ?63 No Yes No
iterations Yes ?63 No Yes No
iterationStart Yes ?63 No Yes No
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support ? ? ?63 ? ? ?
delay ? ? ?63 No No ?
direction ? ? ?63 No No ?
duration ? ? ?63 No No ?
easing ? ? ?63 No No ?
endDelay ? ? ?63 No No ?
fill ? ? ?63 No No ?
iterations ? ? ?63 No No ?
iterationStart ? ? ?63 No No ?

See also

Document Tags and Contributors

Contributors to this page: fscholz, Sheppy, rachelnabors, chrisdavidmills, rolfedh
Last updated by: fscholz,