canPlayAudioMP3.js

/**
 * Detect if the browser can play MP3 audio using native HTML5 Audio.
 * Invokes the callack function with first parameter is the boolean success
 * value; if that value is false, a second error parameter is passed. This error
 * is either HTMLMediaError or some other DOMException or Error object.
 * Note the callback is likely to be invoked asynchronously!
 * @param {function(boolean, Object|undefined)} callback
 */
function canPlayAudioMP3(callback){
	try {
		var audio = new Audio();
		//Shortcut which doesn't work in Chrome (always returns ""); pass through
		// if "maybe" to do asynchronous check by loading MP3 data: URI
		if(audio.canPlayType('audio/mpeg') == "probably")
			callback(true);
		
		//If this event fires, then MP3s can be played
		audio.addEventListener('canplaythrough', function(e){
			callback(true);
		}, false);
		
		//If this is fired, then client can't play MP3s
		audio.addEventListener('error', function(e){
			callback(false, this.error)
		}, false);
		
		//Smallest base64-encoded MP3 I could come up with (<0.000001 seconds long)
		audio.src = "data:audio/mpeg;base64,/+MYxAAAAANIAAAAAExBTUUzLjk4LjIAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA";
		audio.load();
	}
	catch(e){
		callback(false, e);
	}
}