show an animated gif whenever an AJAX called is made

gistfile1.js

Ajax.Responders.register({
	onCreate: function() {
		if($('busy') && Ajax.activeRequestCount>0)
		Effect.Appear('busy',{duration:0.5,queue:'end'});
	},
	onComplete: function() {
		if($('busy') && Ajax.activeRequestCount==0)
		Effect.Fade('busy',{duration:0.5,queue:'end'});
	}
});