js中时间的总结

简单的时间

	let time = new Date()
    console.log(time)  //Wed Sep 11 2019 11:56:13 GMT+0800 (中国标准时间)
    console.log(time.toLocaleDateString())  //2019/9/11
    console.log(time.toLocaleString())  //2019/9/11 上午11:56:13
    console.log(time.toLocaleTimeString())  //上午11:56:13

获取年份

 let timeStr = "2019/6/18"
    var time1 = new Date(timeStr)
    console.log(time1.getFullYear())  //2019

时间转化

  var timeStr2 = "2019-02-19T12:01:00"
    var time2 = new Date(timeStr2)
    console.log(time2)  //Tue Feb 19 2019 12:01:00 GMT+0800 (中国标准时间)

获取计算机开始到现在的毫秒数

// 获取从计算机开始时间到现在的毫秒数
    var curTime = new Date()
    console.log(curTime.getTime())

知道毫秒数，变成时间对象

 //知道毫秒数   变成时间对象
    console.log(new Date(1565594864101)) //Mon Aug 12 2019 15:27:44 GMT+0800 (中国标准时间)

算时间差

  var time1 = new Date("2019-06-18T15:20:25")
    var time2 = new Date("2019-06-20T23:18:19")
    //
    var hms1 = time1.getTime()
    var hms2 =time2.getTime()
    //
    var res = (hms2 - hms1)/1000
    var day = parseInt(res / (24*60*60))
    console.log(day + '天')
    var hour = parseInt((res-day* (24*60*60))/(60*60))
    console.log(hour + '时')
    var second = parseInt((res-day* (24*60*60)-hour*(60*60))/60)
    console.log(second+'分')
    var mit = parseInt((res-day* (24*60*60)-hour*(60*60)-second*60))
    console.log(mit + '秒')

倒计时

//倒计时
    var time1 = new Date("2019-09-12T17:23:00").getTime()
    var timer = setInterval(()=>{
        var time2 = new Date().getTime()
        var res = time1-time2
        if(res < 0){
            clearInterval(timer)
        }else{
            var day = parseInt(res/(24*60*60*1000))
            var hours = parseInt((res-day*60*24*60*1000)/(60*60*1000))
            var minutes = parseInt((res - day*60*24*60*1000-hours*60*60*1000)/(60*1000))
            var ms = parseInt((res - day*60*24*60*1000-hours*60*60*1000 - minutes * 60*1000)/1000)
            var hms = res - day*60*24*60*1000-hours*60*60*1000 - minutes * 60*1000 - ms*1000
            console.log("倒计时："+day + '天' + hours +'时' + minutes + "分"+ms + '秒' + hms + "毫秒数")
        }
    },100)