前台显示服务器倒计时 函数

<script>
function timer(intDiff) {
window.setInterval(function () {
var day = 0,
hour = 0,
minute = 0,
second = 0; //时间默认值
if (intDiff > 0) {
day = Math.floor(intDiff / (60 * 60 * 24));
hour = Math.floor(intDiff / (60 * 60)) - (day * 24);
minute = Math.floor(intDiff / 60) - (day * 24 * 60) - (hour * 60);
second = Math.floor(intDiff) - (day * 24 * 60 * 60) - (hour * 60 * 60) - (minute * 60);
}
if (minute <= 9) minute = '0' + minute;
if (second <= 9) second = '0' + second;
$('.timer_d').html(day + 'Day');
$('.timer_h').html(hour);
$('.timer_m').html(minute);
$('.timer_s').html(second);
intDiff--;
}, 1000);
}
var end_time = new Date('{{activity_end | date:'Y-m-d H:i:s'}}');
var now = new Date();
var leftTime=end_time.getTime()-now.getTime();
timer(leftTime/1000); //倒计时总秒数量
</script>