<!DOCTYPE html>
<html>
<head>
<style>
#myDIV {
    width: 100px;
    height: 100px;
    background: red;
    -webkit-transition: width 2s; /* For Safari 3.1 to 6.0 */
    transition: width 2s;
}


#myDIV:hover {
    width: 400px;
}

</style>
</head>
<body>

<p>Hover over the div element below, and wait for the transition effect to end.</p>

<div id="myDIV"></div>

<p><b>Note:</b> This example does not work in Internet Explorer 9 and earlier versions.</p>

<script>
// Code for Safari 3.1 to 6.0
document.getElementById("myDIV").addEventListener("webkitTransitionEnd", myFunction);

// Standard syntax
document.getElementById("myDIV").addEventListener("transitionend", myFunction);

function myFunction() {
    this.innerHTML = "transitionend event occured - The transition has completed";
    this.style.backgroundColor = "pink";
}
</script>

</body>
</html>