slawekkolodziej

setInterval(function() {
    var time = ((countdownTimestamp * 1000) - new Date()) / 1000,
        h = Math.floor(time / 60),
        s = Math.floor(time % 60),
        title = h + ":" + s;
        
    document.getElementsByTagName("title")[0].textContent = title;
}, 1000);