gistfile1.js

/**
 * thanks to Mark Pilgrim:
 * http://diveintohtml5.org/everything.html
 * http://diveintohtml5.org/detect.html#techniques
 */
function check_html5_audio()
{
  // avoid repeating the check unnecessarily
  if (typeof browser_supports_html5_audio != "undefined")
  {
    return browser_supports_html5_audio;
  }

  browser_supports_html5_audio = false;

  // check if browser supports <audio> tag
  var a = document.createElement('audio');
  if (!a.canPlayType)
  {
    return false;
  }

  // check if browser supports MP3; Firefox supports <audio> but only for Ogg Vorbis
  if (!(a.canPlayType('audio/mpeg;').replace(/no/, '')))
  {
    return false;
  }

  // check if browser supports preload attribute; older versions of Safari do not.
  // for podcast pages, automatically loading every <audio> element on the page is unacceptable.
  // https://bugs.webkit.org/show_bug.cgi?id=25267
  // https://bugs.webkit.org/show_bug.cgi?id=35385
  // http://daringfireball.net/2009/12/html5_video_unusable
  a.setAttribute("preload", "none");
  if (a.preload != "none")
  {
    return false;
  }

  browser_supports_html5_audio = true;
  return true;
}