ValidateSession();

function ValidateSession() {

    var xmlhttp;
    if (window.XMLHttpRequest) {
        // code for IE7+, Firefox, Chrome, Opera, Safari
        xmlhttp = new XMLHttpRequest();
    }
    else if (window.ActiveXObject) {
        // code for IE6, IE5
        xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
    }
    else {
        // alert('browser does not support XMLHTTP.');
    }

    xmlhttp.onreadystatechange = function() {
    if (xmlhttp.readyState == 4) {
            var e = xmlhttp.responseText;
        }
    }

    xmlhttp.open("GET", "/stat-interface/stat-interface.aspx?func=validate&date=" + (new Date()).getTime() + "&res=" + screen.width + " x " + screen.height, true);
    xmlhttp.send(null);
}