如何从html页面传递值？

<form action="/submit" method="post">
  <input type="text" name="username" placeholder="Username">
  <input type="password" name="password" placeholder="Password">
  <button type="submit">Submit</button>
</form>

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

app.use(express.urlencoded({ extended: true }));

app.post('/submit', (req, res) => {
  const username = req.body.username;
  const password = req.body.password;
  console.log(`Username: ${username}, Password: ${password}`);
  res.send('Data received');
});

app.listen(3000, () => {
  console.log('Server is running on port 3000');
});

<a href="/page?param1=value1&param2=value2">Go to Page</a>

app.get('/page', (req, res) => {
  const param1 = req.query.param1;
  const param2 = req.query.param2;
  console.log(`Param1: ${param1}, Param2: ${param2}`);
  res.send('Params received');
});

// 存储数据
localStorage.setItem('username', 'JohnDoe');

// 获取数据
const username = localStorage.getItem('username');
console.log(username);

// 存储数据
sessionStorage.setItem('username', 'JohnDoe');

// 获取数据
const username = sessionStorage.getItem('username');
console.log(username);

fetch('/api/data', {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({ username: 'JohnDoe' })
})
.then(response => response.json())
.then(data => console.log(data))
.catch(error => console.error('Error:', error));

app.post('/api/data', (req, res) => {
  const data = req.body;
  console.log(data);
  res.json({ message: 'Data received' });
});