JS 实现倒计时

 

1.设置截止日期的计时器

 

附代码：

    let endTime = new Date('2021-1-13 18:10:00'); // 截止具体日期
    let time = new Date(endTime)-1; // new Date()-1 === new Date().getTime() 都是转换时间戳的方式
    function downTime(end,tit){
        let now = new Date()-1;
        if(end <= now) {
            app.innerHTML = "00:00:00"
            return 
        }
        let count = end - now;
        let _h = parseInt(count/1000/60/60);
        let _m = parseInt(count/1000/60%60);
        let _s = parseInt(count/1000%60);
        let _d = 0;
        if(_h >= 24) {
            _d = parseInt(_h/24);
            _h = _h - _d*24;
        }
        if(tit && _d === 0 && _h === 0 && _m <= 10) {
            setTimeout(_=>alert("10分钟后截止",_h), 100);
        }
        // 补零function
        let zero = value => value < 10 ? "0" + value : value;  
        app.innerHTML = _d + "天" + zero(_h) + ":" + zero(_m) + ":" + zero(_s);
        setTimeout(_=>downTime(end),1000);
   }
   downTime(time,true);