如何将列表框中的数据插入数据库？

<select id="myList">
  <option value="1">Option 1</option>
  <option value="2">Option 2</option>
  <option value="3">Option 3</option>
</select>

<button onclick="insertData()">Insert Data</button>

<script>
function insertData() {
  var selectedValue = document.getElementById("myList").value;
  
  // 发送请求到后端接口，传递选中的值
  fetch('/insertData', {
    method: 'POST',
    headers: {
      'Content-Type': 'application/json'
    },
    body: JSON.stringify({ value: selectedValue })
  })
  .then(response => response.json())
  .then(data => {
    console.log(data);
    // 处理返回的结果
  })
  .catch(error => {
    console.error('Error:', error);
  });
}
</script>

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

const app = express();
const port = 3000;

// 创建数据库连接
const connection = mysql.createConnection({
  host: 'localhost',
  user: 'root',
  password: 'password',
  database: 'mydatabase'
});

// 连接数据库
connection.connect();

// 创建接口，处理插入数据的请求
app.post('/insertData', (req, res) => {
  const value = req.body.value;

  // 执行插入操作
  const sql = `INSERT INTO mytable (column_name) VALUES ('${value}')`;
  connection.query(sql, (error, results) => {
    if (error) {
      console.error('Error:', error);
      res.status(500).json({ success: false, message: 'Failed to insert data' });
    } else {
      res.json({ success: true, message: 'Data inserted successfully' });
    }
  });
});

// 启动服务器
app.listen(port, () => {
  console.log(`Server listening at http://localhost:${port}`);
});