function createXMLHttpRequestObject()
{
	var resObject = null;
	try 
	{
		resObject = new ActiveXObject("Microsoft.XMLHTTP");
	}
	catch (Error)
	{
		try 
		{
		 	resObject = new ActiveXObject("MSXML2.XMLHTTP");
		}
		catch (Error)
		{
		  	try 
		  	{
		  		resObject = new XMLHttpRequest();
		  	}
		  	catch (Error)
		  	{
				alert("Erzeugung des XMLHttpRequest-Objekts ist nicht moeglich");
		  	}
		}
	}
	return resObject;
}

function CreateAJAXObject()
{
	this.createXMLHttpRequestObject = createXMLHttpRequestObject;
}

o = new CreateAJAXObject();
resObject = o.createXMLHttpRequestObject();