title: Fade out volume of <iframe> with jQuery
body: <p>I'm trying to fade out the volume of a YouTube video embedded in an iframe when the user closes the modal window it is attached to. Instead of having the audio end abruptly, it would be nice to fade the volume slowly. This code isn't working:</p>
  
  <pre><code>$('#youtube-player').animate({volume: 0}, 1000);
  </code></pre>
  
  <p>What else can I try?</p>