根据开始时间和结束时间实现倒计时效果

    getDate() {

      var time_now_server, time_now_client, time_end, time_server_client;

      time_end = new Date("2020 07 22 18:50:50");//结束的时间

      time_end = time_end.getTime();

      time_now_server = new Date("2020 07 21 16:35:35");//开始的时间

      time_now_server = time_now_server.getTime();

      time_now_client = new Date();

      time_now_client = time_now_client.getTime();

      time_server_client = time_now_server - time_now_client;

      var timeFunction = () => {

        var time_now, time_distance, str_time;

        var time_now = new Date();

        time_now = time_now.getTime() + time_server_client;

        time_distance = time_end - time_now;

        if (time_distance > 0) {

          this.day = Math.floor(time_distance / 86400000)

          time_distance -= this.day * 86400000;

          this.h = Math.floor(time_distance / 3600000)

          time_distance -= this.h * 3600000;

          this.m = Math.floor(time_distance / 60000)

          time_distance -= this.m * 60000;

          this.s = Math.floor(time_distance / 1000)

          if (this.h < 10)

            this.h = "0" + this.h;

          if (this.m < 10)

            this.m = "0" + this.m;

          if (this.s < 10)

            this.s = "0" + this.s;

        } else {

          clearInterval(go);

        }

      }

      timeFunction();

      let go = setInterval(function () {

        timeFunction();

      }, 1000);

    },