document.getElementById('f').onsubmit = async e => {
  e.preventDefault();
  const msg = document.getElementById('msg');
  msg.textContent = '';
  const r = await fetch('/api/login', {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({
      name: (document.getElementById('name') as HTMLInputElement).value,
      password: (document.getElementById('pw') as HTMLInputElement).value,
    }),
  });
  if (r.ok) location.href = '/';
  else msg.textContent = await r.text() || 'Sign in failed';
};