<!DOCTYPE html>
<html>
<body>
<script>
function myFunction() { alert('The audio is now playing');
}
</script>
<p>Press play on the audio.</p>
<audio controls onplaying="myFunction()"> <source src="https://download.samplelib.com/mp4/sample-5s.mp4" type="audio/ogg"> <source src="https://download.samplelib.com/mp4/sample-5s.mp4" type="audio/mpeg"> Your browser does not support the audio element.
</audio>
</body>
</html>