自定义倒计时

    newDate(stringTime) {
        // var stringTime = "2021-07-10 10:21:12";
        let timestamp2 = stringTime.replace(/-/g, '/') //为了兼容IOS，需先将字符串转换为'2021/07/10 10:21:12'
        //这一点很重要，一定要在手机端测试
        timestamp2 = Date.parse(timestamp2) //返回'2021-07-10 10:21:12'的时间戳
        let endTimes = timestamp2 + (360 * 60 * 60 * 1000)
        // console.log(stringTime + "的时间戳为：" + timestamp2);
        // console.log('48小时之后的时间戳为：' + endTime)
        this.daojishi(endTimes)
        // return timestamp2;
    },
    daojishi(endTimes) {
        let endTime = endTimes;
        let nowTime = new Date().getTime();
        let Cha = endTime - nowTime;
        let days = parseInt(Cha / 1000 / 60 / 60 / 24, 10); //计算剩余的天数 
        let hours = parseInt(Cha / 1000 / 60 / 60 % 24, 10); //计算剩余的小时 
        let minutes = parseInt(Cha / 1000 / 60 % 60, 10); //计算剩余的分钟 
        let seconds = parseInt(Cha / 1000 % 60, 10); //计算剩余的秒数 
        days = this.checkTime(days);
        hours = this.checkTime(hours);
        minutes = this.checkTime(minutes);
        seconds = this.checkTime(seconds);
        let that = this;//小程序的生命周期和Vue不太一样，所以自调用之前要把this重新定义一下
        setTimeout(function () {
            that.daojishi(endTimes);
        }, 1000);
        let useTime = days + "天" + hours + "小时 " + minutes + "分" + seconds + "秒"
        this.setData({
            useTime: useTime //小程序的赋值方式，假如是普通的Vue语法是不需要这样赋值的
        })
    },
    checkTime(i) { //将0-9的数字前面加上0，例1变为01 
        if (i < 10) {
            i = "0" + i;
        }
        return i;
    },