如何在提交(按钮)选项值(从下拉列表中)后显示警告/文本框？

<form>
  <select id="options">
    <option value="option1">选项1</option>
    <option value="option2">选项2</option>
    <option value="option3">选项3</option>
  </select>
  <input type="submit" value="提交">
</form>

<script>
  const submitButton = document.querySelector('input[type="submit"]');
  submitButton.addEventListener('click', function(event) {
    event.preventDefault(); // 阻止表单默认提交行为

    const selectedOption = document.getElementById('options').value;
    if (selectedOption === 'option1') {
      alert('警告：选项1被选中！');
    } else if (selectedOption === 'option2') {
      const textBox = document.createElement('input');
      textBox.type = 'text';
      document.body.appendChild(textBox);
    }
  });
</script>