$(function(){
    updateEndTime();
});
function updateEndTime() {
    var date = new Date();
    var time = date.getTime();
    $(".settime").each(function(i) {
            var endDate = new Date(this.getAttribute("endTime"));
            var endTime = endDate.getTime();
            var lag = (endTime - time) / 1000;
            if (lag > 0) {
                    var second = Math.floor(lag % 60);
                    var minite = Math.floor((lag / 60) % 60);
                    var hour = Math.floor((lag / 3600) % 24);
                    var day = Math.floor((lag / 3600) / 24);
                    $(this).html(day + "天" + hour + "小时" + minite + "分" + second + "秒");
            }else{
                $(this).html("团购已经结束啦！");
            }
    });
    setTimeout("updateEndTime()", 1000)
};
</script>

??<div class="time fl settime" endTime="unix时间">时间</div>