<!DOCTYPE html>
<html lang="en-US">
<head>
<style>
video{
width:100%;
height:330px
}
</style>
</head>
<body>
<video ondurationchange="myFunction()" controls>
<source src="/hawk.mp4" type="video/mp4">
</video>
<p><strong>Note</strong>: 'ondurationchange' event triggers, when duration of the video changes from 0:00:00 to X:XX:XX</p>
<script>
function myFunction(){
alert("Video duration has changed");
}
</script> </body>
</html>