const App = () => {
  const handlerSubmit = (e) => {
    e.preventDefault();
    window.alert('submit');
  }

  return (
    <div>
      <form onSubmit={ handlerSubmit }>
        <label htmlFor="account">帳號</label>
        <input id="account" type="text" />
        <button type="submit">送出</button>
      </form>
    </div>
  )
}

const app = document.querySelector('#app');
const root = ReactDOM.createRoot(app);
root.render(<App />);