jsp ajax help

function update_item(name, obj)
	{
		
		
		var Name = document.getElementById('Name').value; 
		
		var page = "MyServlet";
		page += "?name=" + name + ";
		
		page += "&action=update";
 
		document.getElementById('updateButton').value='Updating...';
		document.getElementById('updateButton').disabled=true;
 
		var displayloading = true;
		
		var xmlHttp = GetXmlHttpObject();
		
		xmlHttp.onreadystatechange=function()
		{
			document.getElementById('updateButton').value='Update';
			document.getElementById('updateButton').disabled=false;
		}
		
		xmlHttp.open("GET",page,true);
		xmlHttp.send(null);
	}