function loadXMLDoc(url) {
    var ajax;
    // branch for native XMLHttpRequest object
    if (window.XMLHttpRequest) {
        ajax = new XMLHttpRequest();
        ajax.onreadystatechange = processReqChange;
        ajax.open("POST", url, true);
        ajax.send(null);
        // branch for IE/Windows ActiveX version
    } else if (window.ActiveXObject) {
        ajax = new ActiveXObject("Microsoft.XMLHTTP");
        if (ajax) {
            ajax.onreadystatechange = processReqChange;
            ajax.open("POST", url, true);
            ajax.send();
        }
    }
    return ajax;
}