// test for IE version
if (navigator.appName == 'Microsoft Internet Explorer') {
    var ver = -1;
    var ua = navigator.userAgent;
    var re = new RegExp("Windows NT ([0-9]{1,}[\.0-9]{0,})");
    if (re.exec(ua) != null)
        ver = parseFloat(RegExp.$1);
    if (ver >= 5.1) {
        try {
            ev.src = "https://ev.securetrust.com/images/pixel.gif";
        }
        catch (e) { }
    }
}