/**
     *获取当前时间
     *format=1精确到天
     *format=2精确到分
    */
    function getCurrentDate(format) {
      var now = new Date();
      var year = now.getFullYear(); //得到年份
      var month = now.getMonth();//得到月份
      var date = now.getDate();//得到日期
      var day = now.getDay();//得到周几
      var hour = now.getHours();//得到小时
      var minu = now.getMinutes();//得到分钟
      var sec = now.getSeconds();//得到秒
      month = month + 1;
      if (month < 10) month = "0" + month;
      if (date < 10) date = "0" + date;
      if (hour < 10) hour = "0" + hour;
      if (minu < 10) minu = "0" + minu;
      if (sec < 10) sec = "0" + sec;
      var time = "";
      //精确到天
      if(format==1){
        time = year + "-" + month + "-" + date;
      }
      //精确到分
      else if(format==2){
        time = year + "-" + month + "-" + date+ " " + hour + ":" + minu + ":" + sec;
      }
      return time;
    }//格式：2020-06-22 22:43:24

//比较大小，得出它的天数
    function follow_status(value){
        var that_time = Date.parse(getCurrentDate(2));//获取当前时间，并转成时间戳
        var updata_time = Date.parse(value);//你输入的时间，格式：2020-06-20 18:31:30
　　　   //两者相差的天数
        var num_day = (that_time-updata_time)/(1000*60*60*24);
        return num_day
    };

    function timestampToTime(timestamp) {
        var date = ""
        if(timestamp.length == 13) {
            date = new Date(timestamp * 1000);//时间戳为10位需*1000，时间戳为13位的话不需乘1000
        } else {
            date = new Date(timestamp);//时间戳为10位需*1000，时间戳为13位的话不需乘1000
        }
        var Y = date.getFullYear() + ‘-‘;
        var M = (date.getMonth() + 1 < 10 ? ‘0‘ + (date.getMonth() + 1) : date.getMonth() + 1) + ‘-‘;
        var D = date.getDate() + ‘ ‘;
        var h = date.getHours() + ‘:‘;
        var m = date.getMinutes() + ‘:‘;
        var s = date.getSeconds();
        return Y + M + D + h + m + s;
    }
    var date_time = Date.parse("2020-06-20 18:31:30");//转为时间戳
    console.log(timestampToTime(date_time));//2020-06-20 18:31:30