Javascript :Ringtone is not playing

Question

In java script i add

 function startRingTone() {
            try { ringtone.play(); }
            catch (e) { }
        }

        function stopRingTone() {
            try { ringtone.pause(); }
            catch (e) { }
        }

    <audio id="ringtone" loop src="sounds/ringtone.mp3"> </audio>

whenever i call function startringtone();

Sound is not working.

my mp3 file is under sounds/ringtone.mp3.

and I am using MVC 4 so any another additional things needed?