JavaScript 实现基础计数器：setTimeout 与 setInterval 详解

计数器实现代码示例

<!DOCTYPE html>
<html>

  <head>
    <meta charset="UTF-8">
    <script type="text/javascript">
      var c = 0
      var t

      function timedCount() {
        document.getElementById('txt').value = c;
        c = c + 1;
        //创建计时器，在指定周期内循环执行
        t = setTimeout("timedCount()", 1000);
      }

      function stopCount() {
        //清除计时器
        clearTimeout(t);
      }
    </script>
  </head>

  <body>

    <form>
      <input type="button" value="开始计时！" onClick="timedCount()">
      <input type="text" id="txt">
      <input type="button" value="停止计时！" onClick="stopCount()">
    </form>

  </body>

</html>