返回包含 <input type="text"> 元素的表单 id - 在线编辑器

          <!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>蜜蜂教程(mifengjc.com)</title>
  <script>
    function displayResult() {
      var x = document.getElementById("email").form.id;
      alert(x);
    }
  </script>
</head>
<body>

  <form id="form1">
    Email: <input type="text" id="email" value="someone@example.com">
  </form>
  <button type="button" onclick="displayResult()">显示容器表单的id</button>

</body>
</html>
        