function getHttpRequest(handler) { 
	var objXmlHttp = null;
	
	if (navigator.userAgent.indexOf("MSIE") >= 0) { 
		var strName = "Msxml2.XMLHTTP";
		if (navigator.appVersion.indexOf("MSIE 5.5") >= 0) {
			strName = "Microsoft.XMLHTTP";
		}
		try {
			objXmlHttp = new ActiveXObject(strName);
			objXmlHttp.onreadystatechange = handler;
			return objXmlHttp;
		}
		catch (e) {
			alert("Error. Scripting for ActiveX might be disabled") ;
			return null;
		}
	}
	else if (navigator.userAgent.indexOf("Mozilla") >= 0) {
		objXmlHttp = new XMLHttpRequest();
		objXmlHttp.onload = handler;
		objXmlHttp.onerror = handler;
		return objXmlHttp;
	}
	else if (navigator.userAgent.indexOf("Opera") >= 0) {
		alert("This example doesn't work in Opera");
		return null;
	}
}