function GetXMLHttp() {
        
        var xmlHttp;
        try {
        xmlHttp = new XMLHttpRequest();
        }
        catch(ee) {
        try {
        xmlHttp = new ActiveXObject("Msxml2.XMLHTTP");
        }
        catch(e) {
        try {
        xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
        }
        catch(e) {
        xmlHttp = false;
        }
        }
        }
        return xmlHttp;
}

var xmlRequest = GetXMLHttp();