I wrote a small script to "Add to favorites" with AJAX & MooTools and came up with the following:

function addFavorite(id) {
	url = '/includes/add_favorite.php?r='+id;
	new Request({
		url: url,
		method: 'get',
		onSuccess: function(responseText) {
		var myFx = new Fx.Tween('favorite');
		myFx.start('opacity', 0).chain(function(){ 
				$('favorite').set('html', '<a><img src="/images/heart.png" width=24 alt="save"> saved!</a>'); 
				this.set('opacity', 1); 
Which fades the element out, replaces the text and link, then fades it back in.

Is there a better way to write this without having to call the callChain() method? I want to be sure I'm properly chaining methods.