如何根据另一个下拉菜单中的答案创建显示的下拉菜单

 <option value="option1">选项1</option>
 <option value="option2">选项2</option>
 <option value="option3">选项3</option>
</select>

 <option value="">请选择</option>
</select>

const menu1 = document.getElementById('menu1');
const menu2 = document.getElementById('menu2');

menu1.addEventListener('change', function() {
  const selectedOption = menu1.value;
  const xhr = new XMLHttpRequest();
  xhr.open('GET', `https://example.com/api/menu2?option=${selectedOption}`);
  xhr.onload = function() {
    if (xhr.status === 200) {
      const response = JSON.parse(xhr.responseText);
      menu2.innerHTML = '';
      response.forEach(function(item) {
        const option = document.createElement('option');
        option.value = item.value;
        option.textContent = item.label;
        menu2.appendChild(option);
      });
      menu2.style.display = 'block';
    }
  };
  xhr.send();
});

const express = require('express');
const app = express();

app.get('/api/menu2', function(req, res) {
  const option = req.query.option;
  const menu2Options = getMenu2Options(option);
  res.json(menu2Options);
});

function getMenu2Options(option) {
  // 根据option参数返回相应的选项
  // 示例：如果option为option1，则返回选项1的下拉菜单选项
  // 示例：如果option为option2，则返回选项2的下拉菜单选项
  // 示例：如果option为option3，则返回选项3的下拉菜单选项
}

app.listen(3000, function() {
  console.log('Server started on port 3000');
});