<!DOCTYPE html>
<html>
<body>
<p>This example demonstrates how to assign an "onplaying" event to a video element.</p>
<p>Play, pause and then play the video again.</p>
<video controls onplaying="myFunction()">
<source src="movie.mp4" type="video/mp4">
<source src="movie.ogg" type="video/ogg">
Your browser does not support the video tag.
</video>
<script>
function myFunction() {
alert("The video is now playing");
}
</script>
</body>
</html>