HTML 5 <audio> & JavaScript

audio.js

if (typeof Audio != "undefined") { // make sure the browser knows about <audio>
  if (navigator.userAgent.toLowerCase().indexOf("firefox") > -1) { // firefox does not play .mp3 due to licensing issues
    var audioFile = "sound.ogg";
  } else {
    var audioFile = "sound.mp3";
  }  
  
  var audioTag = new Audio(audioFile);
  audioTag.load(); // if you want the file to be loaded right now, use this. otherwise, use it before .play() but be aware that the playback will be delayed then, of course
  
  refreshAudioTag = function() { // workaround for strange chrome behaviour (without calling this, the file won't be played again after it has been played once.)
    audioTag.src = audioFile;
  };
  
  // whenever you want to start the playback, use this:
  refreshAudioTag();
  audioTag.play();
}