如何给网站添加记录当前站点运行了多长时间

<span id="runtime_span" style="color: #9b51e0;font-weight:bold"></span>

<script type="text/javascript">

function show_runtime(){

  window.setTimeout("show_runtime()",1000);

  X = new Date("01/06/2016 5:22:00");

  Y = new Date();

  T = (Y.getTime()-X.getTime());

  M = 24*60*60*1000;

  a = T/M;

  A = Math.floor(a);

  b = (a-A)*24;

  B = Math.floor(b);

  c = (b-B)*60;

  C = Math.floor((b-B)*60);

  D = Math.floor((c-C)*60);

  runtime_span.innerHTML="本站已经稳定运行: "+A+"天"+B+"小时"+C+"分"+D+"秒"

}

show_runtime();

</script>

<template>

    <div class="add-website-long-time">

      <span>{{runTimeText}}</span>

    </div>

  </template>

  <script>

  export default {

      name: 'addLongTime',

      data() {

          return {

              runTimeText: '',

          }

      },

      mounted() {

         this.timer = setInterval(this.runTime,1000);

      },

      methods: {

          runTime() {

            let X = new Date("01/06/2020 5:22:00"); // 设置的初始时间

            let Y = new Date();  // 当前时间

            let T = (Y.getTime()-X.getTime());

            let M =24*60*60*1000;

            let a = T/M;

            let A = Math.floor(a);

            let b = (a-A)*24;

            let B = Math.floor(b);

            let c = (b-B)*60;

            let C = Math.floor((b-B)*60);

            let D = Math.floor((c-C)*60);

            this.runTimeText = "本站已经稳定运行: "+A+"天"+B+"小时"+C+"分"+D+"秒"

         }

      },

      beforeDestroy() {

        clearInterval(this.timer)

      }

  }

  </script>

  <style>

  .add-website-long-time {
      text-align: center;
  }

  </style>
</script>