每个 <p>元素之前插入内容 - 在线编辑器

          <!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <style>
    p:before {
      content: "Read this -";
    }
  </style>
</head>

<body>
  <p>My name is Donald</p>
  <p>I live in Ducksburg</p>

  <p><b>注意:</b> :before 作用于 IE8,DOCTYPE 必须已经声明.</p>

</body>
</html>
        