jQuery fade in only when value has changed

I want #recentTrack to fade out and in, but only when the value for it has changed. At the moment it fades out and in every time the setInterval function is called:

$.getJSON('cache/lastfmCache.json', function(data){     
    $("#recentTrack").html(data.recenttracks.track[0].artist["#text"]); 
}); 
$.get('update.php');

se开发者_如何学编程tInterval(function() {
    $.ajax({url:'cache/lastfmCache.json', dataType:'json',timeout: 5000, success:function(data){
        //if((data.recenttracks.track[0].artist["#text"]) == null) { $.get('update.php'); }
        var x = data.recenttracks.track[0].artist["#text"];
        var y = $("#recentTrack").html();
        if(x != y) {
            $("#recentTrack").fadeOut('slow',function(){ $(this).html(x).fadeIn("slow"); });
            }       
        $.get('update.php');}
    });
}, 10000);

Turns out it was adding a link to the #recentTrack h3. Fixed now.