Someone

var showLoad = eval('function() { loadingContent(\'' + frame + '\'); };');
var showResponse = eval('function(request) { responseContent(request,\'' + frame + '\'); };');
// Create AJAX call
get = get + "&dummy=" + new Date().getTime();
var myAjax = new Ajax.Request( url, {
	method: "get", 
	parameters: get, 
	onLoading: showLoad, 
	onComplete: showResponse
} );