<html>
<head>
<style>
.animated {
left:0px;
width: 100px;
height: 100px;
background-color: red;
animation-name: anim;
animation-duration: 0.25s;
position: relative;
}
/* Standard syntax */
@keyframes anim {
0% {background-color:red; left:0px; top:0px;}
25% {background-color:yellow; left:200px; top:0px;}
50% {background-color:blue; left:200px; top:200px;}
75% {background-color:green; left:0px; top:200px;}
100% {background-color:red; left:0px; top:0px;}
}
</style>
<title>a document</title>
</head>
<body>
<div class="animated" id="animated">hello</div>
<script>
let animated = document.getElementById('animated');
let isStarted = false;
animated.addEventListener('animationstart', function() {
isStarted = true;
});
animated.addEventListener('animationend', function() {
document.title = 'animation finished';
});
// Indicates that no animation has run within a second of document load.
setTimeout(function() {
if (!isStarted)
document.title = 'animation never started';
}, 1000);
</script>
</body>
</html>