js 常用方法记录平时用到的js的一些常用方法，************************************

获取两个时间差值

getIntervalTime(begintime){ // 传入开始计数时间
    let intervalTime = Date.parse(new Date());
    let leave = intervalTime - begintime;
    let hours = Math.floor(leave/(3600*1000)); // 获取小时数 向下取整
    let minutes = Math.floor((leave-hours*3600*1000)/(60*1000))// 获取分钟数
    let secondLeave = leave-hours*3600*1000-minutes*60*1000; // 剩余毫秒数
    let second = Math.floor(secondLeave/(1*1000));
    hours = hours>10?hours:'0'+hours;
    minutes = minutes>10?minutes:'0'+minutes;
    second = second>10?second:'0'+second;
    return `${hours}:${minutes}:${second}`;
},