var zXml /*:Object*/ = {
    useActiveX: (typeof ActiveXObject != "undefined"),
    useDom: document.implementation && document.implementation.createDocument,
    useXmlHttp: (typeof XMLHttpRequest != "undefined")
};

zXml.ARR_XMLHTTP_VERS /*:Array*/ = ["MSXML2.XmlHttp.6.0","MSXML2.XmlHttp.3.0"];

zXml.ARR_DOM_VERS /*:Array*/ = ["MSXML2.DOMDocument.6.0","MSXML2.DOMDocument.3.0"];
                   
/**
 * Static class for handling XMLHttp creation.
 * @class
 */                     
function zXmlHttp() {
}

/**
 * Creates an XMLHttp object.
 * @return An XMLHttp object.
 */
zXmlHttp.createRequest = function ()/*:XMLHttp*/ {

    //if it natively supports XMLHttpRequest object
    if (zXml.useXmlHttp) {
        return new XMLHttpRequest();
    } else if (zXml.useActiveX) { //IE < 7.0 = use ActiveX
  
        if (!zXml.XMLHTTP_VER) {
            for (var i=0; i < zXml.ARR_XMLHTTP_VERS.length; i++) {
                try {
                    new ActiveXObject(zXml.ARR_XMLHTTP_VERS[i]);
                    zXml.XMLHTTP_VER = zXml.ARR_XMLHTTP_VERS[i];
                    break;
                } catch (oError) {                
                }
            }
        }
        
        if (zXml.XMLHTTP_VER) {
            return new ActiveXObject(zXml.XMLHTTP_VER);
        } else {
            throw new Error("Could not create XML HTTP Request.");
        }
    } else {
        throw new Error("Your browser doesn't support an XML HTTP Request.");
    }

};

/**
 * Indicates if XMLHttp is available.
 * @return True if XMLHttp is available, false if not.
 */
zXmlHttp.isSupported = function ()/*:Boolean*/ {
    return zXml.useXmlHttp || zXml.useActiveX;
};