如何用javascript写登录注册

登录注册通常需要与后端进行交互，因此需要使用AJAX或者Fetch等方式将数据提交给后端进行处理。以下是一个简单的使用Javascript和AJAX实现登录注册的示例代码：

1. 登录

HTML代码：

<form id="login-form">
  <label for="email">Email：</label>
  <input type="email" id="email" name="email" required>
  <br>
  <label for="password">Password：</label>
  <input type="password" id="password" name="password" required>
  <br>
  <button type="submit">Login</button>
</form>

Javascript代码：

const loginForm = document.querySelector('#login-form');

loginForm.addEventListener('submit', async (event) => {
  event.preventDefault();
  const formData = new FormData(loginForm);
  try {
    const response = await fetch('/api/login', {
      method: 'POST',
      body: formData
    });
    if (response.ok) {
      // 登录成功
      const result = await response.json();
      console.log(result);
    } else {
      // 登录失败
      console.error('登录失败');
    }
  } catch (error) {
    console.error(error);
  }
});

2. 注册

HTML代码：

<form id="register-form">
  <label for="email">Email：</label>
  <input type="email" id="email" name="email" required>
  <br>
  <label for="password">Password：</label>
  <input type="password" id="password" name="password" required>
  <br>
  <label for="confirm-password">Confirm Password：</label>
  <input type="password" id="confirm-password" name="confirm-password" required>
  <br>
  <button type="submit">Register</button>
</form>

Javascript代码：

const registerForm = document.querySelector('#register-form');

registerForm.addEventListener('submit', async (event) => {
  event.preventDefault();
  const formData = new FormData(registerForm);
  const password = formData.get('password');
  const confirmPassword = formData.get('confirm-password');
  if (password !== confirmPassword) {
    console.error('两次输入密码不一致');
    return;
  }
  try {
    const response = await fetch('/api/register', {
      method: 'POST',
      body: formData
    });
    if (response.ok) {
      // 注册成功
      const result = await response.json();
      console.log(result);
    } else {
      // 注册失败
      console.error('注册失败');
    }
  } catch (error) {
    console.error(error);
  }
});

以上代码仅供参考，实际情况需要根据后端接口的实现进行相应的修改。