Mine

var ajx = Ajax.getInstance();
					var url = "./index.php?act=" + id;
					ajx.open("GET", url, true);
					ajx.onreadystatechange = function(){
						if (ajx.readyState==1) {
							var divHTML = '<div align="center"><b>Processing your request</b><br/><img src="images/loading.gif"></div>';
							document.getElementById('innercont').innerHTML = divHTML;
						}else if(ajx.readyState==4){
							if (ajx.status==200){
								document.getElementById('innercont').innerHTML = ajx.responseText;
							}
							Ajax.release(ajx);
						}
					};
					ajx.send("");