当按钮被点击时执行JavaScript代码 - 在线编辑器

          <!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>蜜蜂教程(mifengjc.com)</title>
  <script>
    function myFunction() {
      document.getElementById("demo").innerHTML = "Hello World";
    }
  </script>
</head>
<body>

  <p>单击按钮触发函数。</p>
  <button onclick="myFunction()">点我</button>
  <p id="demo"></p>

</body>
</html>
        