改变 counter-reset 属性 - 在线编辑器

          <!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>蜜蜂教程(mifengjc.com)</title>
  <style>
    h1:before {
      counter-increment: section;
      content: "第 " counter(section) " 部分：";
    }
  </style>
</head>
<body>

  <p>点击“尝试一下”按钮设置 BODY 元素的 counter-reset 属性：</p>
  <button onclick="myFunction()">尝试一下</button>
  <h1>HTML 教程</h1>
  <h1>JavaScript 教程</h1>
  <h1>CSS 教程</h1>
  <script>
    function myFunction() {
      document.body.style.counterReset = "section";
    }
  </script>

</body>
</html>
        