HTMLElement: animationiteration event

The animationiteration event is fired when an iteration of a CSS Animation ends, and another one begins. This event does not occur at the same time as the animationend event, and therefore does not occur for animations with an animation-iteration-count of one.

Bubbles Yes
Cancelable No
Interface AnimationEvent
Event handler property onanimationiteration


This code uses animationiteration to keep track of the number of iterations an animation has completed:

const animated = document.querySelector('.animated');

let iterationCount = 0;

animated.addEventListener('animationiteration', () => {
  console.log(`Animation iteration count: ${iterationCount}`);

The same, but using the onanimationiteration event handler property:

const animated = document.querySelector('.animated');

let iterationCount = 0;

animated.onanimationiteration = () => {
  console.log(`Animation iteration count: ${iterationCount}`);

Live example


<div class="animation-example">
    <div class="container">
        <p class="animation">You chose a cold night to visit our planet.</p>
    <button class="activate" type="button">Activate animation</button>
    <div class="event-log"></div>


.container {
  height: 3rem;

.event-log {
  width: 25rem;
  height: 2rem;
  border: 1px solid black;
  margin: 0.2rem;
  padding: 0.2rem;
} {
  animation-duration: 2s;
  animation-name: slidein;
  animation-iteration-count: 2;

@keyframes slidein {
  from {
    transform: translateX(100%) scaleX(3);
  to {
    transform: translateX(0) scaleX(1);


const animation = document.querySelector('p.animation');
const animationEventLog = document.querySelector('.animation-example>.event-log');
const applyAnimation = document.querySelector('.animation-example>button.activate');
let iterationCount = 0;

animation.addEventListener('animationstart', () => {
  animationEventLog.textContent = `${animationEventLog.textContent}'animation started' `;

animation.addEventListener('animationiteration', () => {
  animationEventLog.textContent = `${animationEventLog.textContent}'animation iterations: ${iterationCount}' `;

animation.addEventListener('animationend', () => {
  animationEventLog.textContent = `${animationEventLog.textContent}'animation ended'`;
  applyAnimation.textContent = "Activate animation";

animation.addEventListener('animationcancel', () => {
  animationEventLog.textContent = `${animationEventLog.textContent}'animation canceled'`;

applyAnimation.addEventListener('click', () => {
  animationEventLog.textContent = '';
  iterationCount = 0;
  let active = animation.classList.contains('active');
  if (active) {
    applyAnimation.textContent = "Cancel animation";
  } else {
    applyAnimation.textContent = "Activate animation";



Specification Status Comment
CSS Animations Working Draft Initial definition

Browser compatibility

Update compatibility data on GitHub
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
animationiteration eventChrome Full support 43Edge Full support 12Firefox Full support 51IE Full support 10Opera Full support 30Safari Full support 9WebView Android Full support 43Chrome Android Full support 43Firefox Android Full support 51Opera Android Full support 30Safari iOS Full support 9Samsung Internet Android Full support 4.0


Full support  
Full support

See also