js内置对象Date

    var now = new Date()//获取当前时间

    var now1 = new Date("2020-05-21 15:14:20")//设置时间
    var now2 = now1 - now
    console.log(now2)//两个时间之间的差值

    let yy = now.getFullYear()//获取年
    let mm = now.getMonth()//获取月
    let dd = now.getDate()//获取日
    let hh = now.getHours()//获取时
    let mi = now.getMinutes()//获取分
    let ss = now.getSeconds()//获取秒
    let ww = "星期" + "日一二三四五六"[now.getDay()]//获取星期