function startAjax() { //appropriate to browser being used
    var xmlHttpObj;
    if (window.XMLHttpRequest)
    xmlHttpObj = new XMLHttpRequest();
    else {
        try { xmlHttpObj = new ActiveXObject("Msxml2.XMLHTTP"); }
        catch (e) {
            try { xmlHttpObj = new ActiveXObject("Microsoft.XMLHTTP"); }
            catch (e) { xmlHttpObj = false; }
        }
    }
    return xmlHttpObj;
}