var ajax_elem;
function ajax_send(url, elem) {
    ajax_elem  = document.getElementById(elem);
    if (url) {
        if (window.XMLHttpRequest) { // Gecko browsers
            ajax_request = new XMLHttpRequest();
            if (ajax_request.overrideMimeType) {
                ajax_request.overrideMimeType("text/xml");
            }
        } else if (window.ActiveXObject) { // IE-Engine
            try {
                ajax_request = new ActiveXObject("Msxml2.XMLHTTP");
            } catch (e) {
                try {
                   ajax_request = new ActiveXObject("Microsoft.XMLHTTP");
                } catch (e) {} 
            }
        }
        if (!ajax_request) {
            alert("Transaction closed: xlmhttp could not be instantiate");
        }
        // callback function is called
        ajax_request.onreadystatechange = ajax_handleChanges;
        ajax_request.open("GET", url, true);
        ajax_request.send(null); // data as argument if opened with POST
    }
}

function ajax_handleChanges() {
    if (ajax_request.readyState == 4){
        if (ajax_request.status == 200) {
            ajax_resp  = ajax_request.responseText;
            ajax_elem.innerHTML = ajax_resp;
        } else {
            alert("server-error : " + ajax_request.statusText);
        }
    }
}