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

The Web Animations API dictionary EffectTiming's iterations property specifies the number of times the animation should repeat. The default value is 1, indicating that it should only play once, but you can set it to any floating-point value (including positive Infinity defaults to 1, and can also take a value of Infinity to make it loop infinitely. 

Element.animate(), KeyframeEffectReadOnly(), and KeyframeEffect() all accept an object of timing properties including iterations. The value of iterations corresponds directly to AnimationEffectTimingReadOnly.iterations in timing objects returned by AnimationEffectReadOnly, KeyframeEffectReadOnly, and KeyframeEffect.


var timingProperties = {
  iterations: numberOfIterations

timingProperties.iterations = numberOfIterations;


A floating-point value specifying the number of times the animation sequence will play through. Any value from 0 (don't play the animation at all) to positive Infinity (run the animation indefinitely) is supported. Defaults to 1, meaning the animation sequence plays through once then stops automatically.


An attempt was made to set the value of this property to a negative number or NaN. The property's value is left unchanged.


In the Forgotten Key example, Alice waves her arm up and down the entire time the page is open by passing Infinity as the value for her iterations property:

// Get Alice's arm, and wave it up and down
  { transform: 'rotate(10deg)' }, 
  { transform: 'rotate(-40deg)' }
], {
  easing: 'steps(2, end)',
  iterations: Infinity,
  direction: 'alternate',
  duration: 600


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

Browser compatibility

Update compatibility data on GitHub
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
Chrome Full support 52Edge Full support ≤79Firefox Full support 63IE No support NoOpera Full support YesSafari No support NoWebView Android Full support 52Chrome Android Full support 52Firefox Android Full support 63Opera Android No support NoSafari iOS No support NoSamsung Internet Android Full support 6.0


Full support  
Full support
No support  
No support
Experimental. Expect behavior to change in the future.
Experimental. Expect behavior to change in the future.

See also