<!DOCTYPE html> <html lang="en">      <head>         <meta charset="UTF-8">         <title>Title</title>         <style>             #showTime {                 width: 300px;                 height: 60px;                 font-size: 60px;                 line-height: 60px;             }         </style>     </head>      <body>         <div>             <div id="showTime">00:00:00</div>             <button id="startBn">启动</button>             <button id="restBn">复位</button>         </div>         <script>                          var time, showTime, startBn, restBn, pauseDate;                          var bool = false;                          var pauseTime = 0;              init();             function init() {                 showTime = document.getElementById("showTime");                 startBn = document.getElementById("startBn");                 restBn = document.getElementById("restBn");                 startBn.addEventListener("click", clickHandler);                 restBn.addEventListener("click", clickHandler);                 setInterval(animation, 16);             }                           function animation() {                 if (!bool) return;                                  var times = new Date().getTime() - time - pauseTime;                 var minutes = Math.floor(times / 60000);                 var seconds = Math.floor((times - minutes * 60000) / 1000);                                  var ms = Math.floor((times - minutes * 60000 - seconds * 1000) / 10);                 showTime.innerHTML =                     (minutes < 10 ? "0" + minutes : minutes) + ":"                     + (seconds < 10 ? "0" + seconds : seconds) + ":"                     + (ms < 10 ? "0" + ms : ms);             }                           function clickHandler(e) {                 e = e || window.event;                 if (this === startBn) {                     bool = !bool;                     if (bool) {                         this.innerHTML = "暂停";                                                                           pauseTime += (!pauseDate ? 0 : new Date().getTime() - pauseDate);                         if (time) return;                         time = new Date().getTime();                         return;                     }                      this.innerHTML = "启动";                     pauseDate = new Date().getTime();                     return;                 }                 startBn.innerHTML = "启动";                 pauseTime = 0;                 pauseDate = null;                 bool = false;                 time = 0;                 showTime.innerHTML = "00:00:00";             }          </script>     </body>  </html>