Best Auto Refresh Technique

I have a swf file that dynamically reads the ID3 tag of what I have playing on my Internet radio station. It then shows what is currently playing and has a button to login to the stream.

Right now I am using setInterval to check and see if the song has changed and I was wondering if there is a better way to do it?

Right now my code looks as follows:

songInfo = function()	{
	loadText = new LoadVars();
	loadText.onLoad = function() {
	song =;
	album = this.album;
	artist = this.artist;
	final = (song + album + "<B>" + artist + "</B>");

setInterval(songInfo, 50);

Does anyone know if there is a way to only reload if the data in trackinfo.txt changes?