function Ajax(szUrl, pfnCallback, szPost)
{
	var http = ( window.ActiveXObject ? new ActiveXObject("Microsoft.XMLHTTP") : new XMLHttpRequest() );
	if( http )
	{
		if( szPost == null ) // get method
		{
			http.open("GET", szUrl);
		}
		else // post method
		{
			http.open("POST", szUrl);
			http.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
			http.setRequestHeader("Content-length", szPost.length);
			http.setRequestHeader("Connection", "close");
		}

		http.onreadystatechange = function()
		{
			if( http.readyState == 4 )
			{
				pfnCallback(http.responseXML);
			}
		};

		http.send(szPost);
	}
	else
	{
		alert("Your browser does not support AJAX!");
	}
}

function xmlGetValue(obj)
{
	var t = obj.firstChild;
	return ( t ? t.nodeValue : '' );
}