处理多个select的post请求

<select name="select1">
  <option value="option1">Option 1</option>
  <option value="option2">Option 2</option>
  <option value="option3">Option 3</option>
</select>

<select name="select2">
  <option value="option1">Option 1</option>
  <option value="option2">Option 2</option>
  <option value="option3">Option 3</option>
</select>

<!-- 可以添加更多的select元素 -->

var selectedValues = {};

// 获取select1的选中值
selectedValues.select1 = document.getElementsByName('select1')[0].value;

// 获取select2的选中值
selectedValues.select2 = document.getElementsByName('select2')[0].value;

// 可以添加更多的select元素的选中值获取

var xhr = new XMLHttpRequest();
xhr.open('POST', '/api/endpoint', true);
xhr.setRequestHeader('Content-Type', 'application/json');

xhr.onreadystatechange = function() {
  if (xhr.readyState === 4 && xhr.status === 200) {
    // 请求成功处理逻辑
    console.log(xhr.responseText);
  }
};

xhr.send(JSON.stringify(selectedValues));

const express = require('express');
const bodyParser = require('body-parser');

const app = express();
app.use(bodyParser.json());

app.post('/api/endpoint', (req, res) => {
  const selectedValues = req.body;
  
  // 处理选中值的逻辑
  // ...

  res.send('处理成功');
});

app.listen(3000, () => {
  console.log('服务器已启动');
});