function createXMLHttpRequest() {
    var xmlhttp;
    try {
        xmlhttp = new ActiveXObject('Msxml2.XMLHTTP');
    } catch(e) {
        try {
            xmlhttp = new ActiveXObject('Microsoft.XMLHTTP');
        } catch(e) {
            try {
                xmlhttp = new XMLHttpRequest();
            } catch(e) {
                alert("Can't create XMLHttpRequest object!");
            }
        }
    }
    return xmlhttp;
}