Mine

		new Ajax.Updater("feed"+id,"../items/getFeed", {
		  method:'post',
		  parameters: hash,
		  onComplete: function(transport){
		  	Effect.toggle(feedbox, 'blind');
		  },
			onFailure : function(resp) {
				alert("Oops there's been an error, try submitting again.");
			}
		});