var maxtime = {{$startt}}; //一个小时，按秒计算，自己调整!
    var timespan=$('.unstart span');
    function formatZero(num, len) {
        if(String(num).length > len) return num;
        return (Array(len).join(0) + num).slice(-len);
    }
    function CountDown() {
        if (maxtime >= 1) {
            hours=Math.floor(maxtime / 3600);
            lastmil=Math.floor(maxtime % 3600);
            minutes = Math.floor(lastmil / 60);
            seconds = Math.floor(lastmil % 60);
            msg = formatZero(hours,2) + ":" +formatZero(minutes,2) + ":" + formatZero(seconds,2);
            timespan.text(msg);
            maxtime--;
        } else{
            clearInterval(timer);
            window.location.reload();
        }
    }
    if(maxtime<=60)timer = setInterval("CountDown()", 1000);