function createXMLHttp() {
        if(typeof XMLHttpRequest != "undefined") {
                return(new XMLHttpRequest());
        } else if(window.ActiveXObject) {
                var aVersions = [ "MSXML2.XMLHttp.5.0",
                                                  "MSXML2.XMLHttp.4.0",
                                                  "MSXML2.XMLHttp.3.0",
                                                  "MSXML2.XMLHttp",
                                                  "Micrososft.XMLHttp"
                                                ];
                for(i=0; i<aVersions.length; i++) {
                        try {
                                var oXmlHttp = new ActiveXObject(aVersions[i]);
                                return(oXmlHttp);
                        } catch(oError) {
                                // do nothing
                        }
                }
        }
}