Standard XmlHttpRequest using JScript

// Standard XmlHttpRequest using JScript
 sendXmlHttpRequest = function (xml){

        //send the xml request and return  the responseXML
        var xmlHttpRequest = new ActiveXObject("Msxml2.XMLHTTP");
        xmlHttpRequest.Open("POST", "http://service url", false);
        xmlHttpRequest.setRequestHeader("SOAPAction",'http://schemas.microsoft.com/crm/2007/WebServices/RetrieveMultiple');
        xmlHttpRequest.setRequestHeader("Content-Type", "text/xml; charset=utf-8");
        xmlHttpRequest.setRequestHeader("Content-Length", xml.length);
        xmlHttpRequest.send(xml);
        if (xmlHttpRequest.responseXML == null || xmlHttpRequest.responseXML.xml == null || xmlHttpRequest.responseXML.xml == "") {
            if (xmlHttpRequest.responseText != null && xmlHttpRequest.responseText != "")
                throw new Error(xmlHttpRequest.responseText);
            else
                throw new Error("Error returning response");
        }
        var responseXML = xmlHttpRequest.responseXML;
        if (xmlHttpRequest.responseXML.documentElement.selectNodes("//error/description").length > 0) {
            throw new Error(responseXML.xml);
        }

        return responseXML;
    }