Answer by Alexis Abril for Javascript Add Event Listener for change in Audio Volume

You're looking for the "volumechange" event.

var audio = document.getElementById('sample');audio.addEventListener('volumechange', function() {    console.log('changed.', arguments);}, false);

I'm using the bubble phase(as opposed to capture) in this example.

http://jsfiddle.net/426E6/

http://www.w3.org/html/wg/drafts/html/master/embedded-content-0.html#event-definitions