js实现注册登录功能实现的

<!-- 注册页面 -->
<form id="registerForm">
    <input type="text" id="username" placeholder="用户名" required>
    <input type="password" id="password" placeholder="密码" required>
    <button type="submit">注册</button>
</form>

<!-- 登录页面 -->
<form id="loginForm">
    <input type="text" id="loginUsername" placeholder="用户名" required>
    <input type="password" id="loginPassword" placeholder="密码" required>
    <button type="submit">登录</button>
</form>

document.getElementById('registerForm').addEventListener('submit', function(event) {
    event.preventDefault();
    const username = document.getElementById('username').value;
    const password = document.getElementById('password').value;

    fetch('/api/register', {
        method: 'POST',
        headers: {
            'Content-Type': 'application/json'
        },
        body: JSON.stringify({ username, password })
    }).then(response => response.json())
      .then(data => {
          if (data.success) {
              alert('注册成功');
          } else {
              alert('注册失败: ' + data.message);
          }
      });
});

document.getElementById('loginForm').addEventListener('submit', function(event) {
    event.preventDefault();
    const username = document.getElementById('loginUsername').value;
    const password = document.getElementById('loginPassword').value;

    fetch('/api/login', {
        method: 'POST',
        headers: {
            'Content-Type': 'application/json'
        },
        body: JSON.stringify({ username, password })
    }).then(response => response.json())
      .then(data => {
          if (data.success) {
              alert('登录成功');
              // 可以在这里进行页面跳转或其他操作
          } else {
              alert('登录失败: ' + data.message);
          }
      });
});

const express = require('express');
const bodyParser = require('body-parser');
const app = express();
app.use(bodyParser.json());

const users = []; // 模拟数据库

app.post('/api/register', (req, res) => {
    const { username, password } = req.body;
    if (users.find(user => user.username === username)) {
        return res.json({ success: false, message: '用户名已存在' });
    }
    users.push({ username, password });
    res.json({ success: true });
});

app.post('/api/login', (req, res) => {
    const { username, password } = req.body;
    const user = users.find(user => user.username === username && user.password === password);
    if (user) {
        res.json({ success: true });
    } else {
        res.json({ success: false, message: '用户名或密码错误' });
    }
});

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