var XmlHttp;

function createXmlHttpRequest( handler ) {
var XmlHttp = null;
if (navigator.userAgent.indexOf("Opera") >= 0) {
alert ("Opera is not supported i guess... use FF");
return;
}
if (navigator.userAgent.indexOf("MSIE") >= 0) {

var strName = "Msxml2.XMLHTTP"

if (navigator.appVersion.indexOf("MSIE 5.5") >= 0) {

strName = "Microsoft.XMLHTTP";

}

try {

XmlHttp = new ActiveXObject(strName)
XmlHttp.onreadystatechange = handler;
return XmlHttp;

} catch(e) {

alert("Error. Scripting for ActiveX might be disabled");
return;

}

}

if (navigator.userAgent.indexOf("Mozilla") >= 0 ) {

XmlHttp = new XMLHttpRequest();
XmlHttp.onload = handler;
XmlHttp.onerror = handler;
return XmlHttp;

}

}