function SetCounter() {
    var hh = $("#Hours");
    var mm = $("#Minutes");
    var ss = $("#Seconds");

    var h = parseFloat(hh.text());
    var m = parseFloat(mm.text());
    var s = parseFloat(ss.text());

    s = s - 1;
    if (s < 0) {
        s = 59;
        m = m - 1;
        if (m < 0) {
            m = 59;
            h = h - 1;
            if (h < 0) {
                h = h - 23;
            }
        }
    }
    hh.text(h > 9 ? h : "0" + h);
    mm.text(m > 9 ? m : "0" + m);
    ss.text(s > 9 ? s : "0" + s);
}

window.setInterval("SetCounter()", 1000);