How Do I Play A Sound When An Element Changes, Like So Chat Does?

I want a sound to play when an element changes on a page. I know how to do this, but I can't get it to play only on the first change, and don't do it later, until the user focuses

Solution 1:

Use a variable to represent whether the sound should be played or not.

var shouldPlayAlertSound = true,
    notif = newAudio('http://cycle1500.com/sounds/infbego.wav');
if (window.innerHeight === window.outerHeight) {
  $(window).bind({
    'DOMNodeInserted': function() {
      if (shouldPlayAlertSound) {
        notif.play();
      }
      shouldPlayAlertSound = false;
    }, blur: function() {
      shouldPlayAlertSound = true;
    } 
  });
}

Edit: I've tested this working on Firefox, Safari, and Opera (except for the innerHeight check). (Chrome doesn't support playing WAV audio files, only the MP3, AAC, or Ogg Vorbis formats.)

Solution 2:

If this is your only DOMNodeInserted handler, I'd just remove it when the work is done (making all future insertions cheaper), like this:

notif = newAudio('http://cycle1500.com/sounds/infbego.wav');
if (window.innerHeight === window.outerHeight) {
  $(window).bind({
    'DOMNodeInserted': function() { 
      notif.play(); 
      $(window).unbind('DOMNodeInserted'); 
    }
  });
}

If it's not the only handler that's workable too, just make it a named function:

notif = newAudio('http://cycle1500.com/sounds/infbego.wav');
if (window.innerHeight === window.outerHeight) {
  functionplay() { notif.play(); $(window).unbind('DOMNodeInserted', play); }
  $(window).bind({
    'DOMNodeInserted': play
  });
}