node连接MySQL后，前端表单查询搜不到数据库内容，如何解决？

node连接后端MySQL，前端利用HTML写了一个最简单的form表单做测试，输入账号密码之后node终端查询空，具体代码如下：

const http = require('http');
const querystring = require('querystring');
const mysql = require('mysql')
const server = http.createServer((req, res) => {
    let postVal = "";
    req.on("data", (chunk) => {
        postVal += chunk;
    })
    req.on("end", () => {
        let formVal = querystring.parse(postVal);
        let userName = formVal.userName;
        let userPwd = formVal.userPwd;

        const connection = mysql.createConnection({
            host: "localhost",
            user: "root",
            password: "123456",
            port: 3306,
            database: "demo1"
        })
        // 连接
        connection.connect();
        // 查询
        connection.query('select * from user where userName=? and userPwd=?', [userName, userPwd], (err,
            result, fields) => {
            if (err) throw err;
            if (result.length > 0) {
                res.writeHead(200, {'Content-type':'text/html;charset=utf8'})
                res.write(result);
            }
            res.end();
        })
        connection.end();
    })
})
server.listen(8080)
console.log('server is running...')

前端代码如下：

<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8">
        <title>node_test</title>
    </head>
    <body>
        <form method="post" action="http://localhost:8080">
            <input type="text" name="userUser"/>
            <input type="password" name="userPwd"/>
            <input type="submit" name="登录"/>
        </form>
    </body>
</html>