function createXHR()
{
    if (typeof XMLHttpRequest != "undefined") {
        return new XMLHttpRequest();
    } else if (window.ActiveXObject) {
        var aVersions = [ "MSXML2.XMLHttp.6.0", "MSXML2.XMLHttp.3.0"];
        for (var i = 0; i < aVersions.length; i++) {
    try {
        var oXHR = new ActiveXObject(aVersions[i]);
        return oXHR;
    } catch (oError) {
        //Do nothing
        }
    }
}
throw new Error("XMLHttp object could not be created.");
}

function encodeNameAndValue(sName, sValue) {
var sParam = encodeURIComponent(sName);
sParam += "=";
sParam += encodeURIComponent(sValue);
return sParam;
}