JavaScript倒計時

/
var countdown = new CountDown(
    document.getElementById('countdown_wrapper'), 
    new Date(2015, 8, 27, 0, 0)
);
countdown.run();/
var CountDown = function(wrapper, endDate) {
    // init
    this.wrapper = wrapper;
    this.timerRunning = false;
    this.endDate = endDate;
    this.template = '{days} DAYS {hours} HOURS {mins} MINS {secs} SECS';
}
CountDown.prototype.showtime = function(){
    var now = new Date();
    var leftTime = this.endDate.getTime() - now.getTime();
    var leftsecond = parseInt(leftTime / 1000);
    var day1 = Math.floor(leftsecond / (60  60  24));
    var hour1 = Math.floor((leftsecond - day1  24  60  60) / 3600);
    var hour = Math.floor((leftsecond - 60  60) / 3600);
    if (hour < 0) {
        hour = 0;
    }
    if (day1 < 0) {
        hour = hour1
    }
    var minute = Math.floor((leftsecond - day1  24  60  60 - hour1  3600) / 60);
    var second = Math.floor(leftsecond - day1  24  60  60 - hour1  3600 - minute * 60);
    var html = '';
    if (leftTime > 0) {
        html = this.template;
        html = html.replace('{days}', day1);
        html = html.replace('{hours}', hour1);
        html = html.replace('{mins}', minute);
        html = html.replace('{secs}', second);
        this.wrapper.innerHTML = html;
    } else {
        html = this.template;
        html = html.replace('{days}', 0);
        html = html.replace('{hours}', 0);
        html = html.replace('{mins}', 0);
        html = html.replace('{secs}', 0);
        this.wrapper.innerHTML = html;
    }
    this.timerRunning = true;

}
CountDown.prototype.run = function(){
    var _this = this;
    CountDown_timer = setTimeout(function() {
        _this.showtime();
        CountDown_timer = setTimeout(arguments.callee, 1000);
        _this.timerRunning = true;
    }, 1000);
}
CountDown.prototype.stop = function(){
    if(timerRunning)
        clearTimeout(CountDown_timer);
    this.timerRunning = false;
}
CountDown.prototype.constructor = CountDown;</pre>