function callAjax(url, pageElement, callMessage, errorMessage) {
    document.getElementById(pageElement).innerHTML = callMessage;
    try {
    req = new XMLHttpRequest(); /* e.g. Firefox */
    } catch(e) {
    try {
    req = new ActiveXObject("Msxml2.XMLHTTP"); /* some versions IE */
    } catch (e) {
    try {
    req = new ActiveXObject("Microsoft.XMLHTTP"); /* some versions IE */
    } catch (E) {
    req = false;
    }
    }
    }
    req.onreadystatechange = function() {responseAjax(pageElement, errorMessage);};
    req.open("GET",url,true);
    req.send(null);
    }

    function responseAjax(pageElement, errorMessage) {
    var output = '';
    if(req.readyState == 4) {
    if(req.status == 200) {
    output = req.responseText;
    document.getElementById(pageElement).innerHTML = output;
    } else {
    document.getElementById(pageElement).innerHTML = errorMessage+"\n"+output;
    }
    }
    }