如何从单独的文件中使用表单部分？

<form>
  <label for="name">姓名：</label>
  <input type="text" id="name" name="name" required><br><br>
  
  <label for="email">邮箱：</label>
  <input type="email" id="email" name="email" required><br><br>
  
  <label for="message">留言：</label>
  <textarea id="message" name="message" required></textarea><br><br>
  
  <input type="submit" value="提交">
</form>

document.querySelector('form').addEventListener('submit', function(event) {
  event.preventDefault(); // 阻止表单默认提交行为
  
  // 获取表单数据
  var name = document.getElementById('name').value;
  var email = document.getElementById('email').value;
  var message = document.getElementById('message').value;
  
  // 执行表单提交的后续操作，例如发送数据到服务器或进行表单验证等
  // ...
});

<div id="form-container"></div>

<script src="form.js"></script>
<script>
  fetch('form.html')
    .then(response => response.text())
    .then(html => {
      document.getElementById('form-container').innerHTML = html;
    });
</script>