抢购倒计时 demo

function countDate(_start, _end, _this)
{
    var now = new Date();
    var time = now.getTime();
    var now_sec = Math.floor(time/1000);//获得当前的秒级时间戳
    if(now_sec < _start){
        var leftsecond = _start - now_sec; //计算时间戳差值
        var day=Math.floor(leftsecond/(3600*24))
        var hour=Math.floor((leftsecond-day*3600*24)/3600);
        var minute=Math.floor((leftsecond-day*3600*24-hour*3600)/60);
        var second=Math.floor(leftsecond-day*3600*24-hour*3600-minute*60);
        var dateHtml = '即将开始：<b>'+day+'天'+hour+'小时'+minute+'分'+second+'秒</b>，快叫上好友一起来抢购吧~';
    }else if(_start <= now_sec && now_sec < _end){
        var leftsecond = _end - now_sec; //计算时间戳差值
        var day=Math.floor(leftsecond/(3600*24))
        var hour=Math.floor((leftsecond-day*3600*24)/3600);
        var minute=Math.floor((leftsecond-day*3600*24-hour*3600)/60);
        var second=Math.floor(leftsecond-day*3600*24-hour*3600-minute*60);
        var dateHtml = '剩余：<b>'+day+'天'+hour+'小时'+minute+'分'+second+'秒</b>，抓住机会来抢购吧~';
    }else if(_end <= now_sec){
        var dateHtml = '已结束'
    }
    _this.html(dateHtml);
}