function FactoryXMLHttpRequest() {
    if( window.XMLHttpRequest) {
        return new XMLHttpRequest();
    }
    else if( window.ActiveXObject) {
        var msxmls = new Array(
            'Msxml2.XMLHTTP.5.0',
            'Msxml2.XMLHTTP.4.0',
            'Msxml2.XMLHTTP.3.0',
            'Msxml2.XMLHTTP',
            'Microsoft.XMLHTTP');
        for (var i = 0; i < msxmls.length; i++) {
            try {
                return new ActiveXObject(msxmls[i]);
            } catch (e) {
            }
        }
    }
    throw new Error( "Could not instantiate factory");
}