index-4l

HTML

<!DOCTYPE html>
<html lang="en">

  <head>
    <meta charset="UTF-8">
    <title>React</title>
  </head>

  <body>
    <div id="root"></div>
    <script crossorigin src="https://unpkg.com/react@18/umd/react.development.js"></script>
    <script crossorigin src="https://unpkg.com/react-dom@18/umd/react-dom.development.js"></script>
  </body>

</html>

Babel + JSX

class MyForm extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      mycar: 'Volvo'
    };
  }
  render() {
    return (
      <form>
      <select value={this.state.mycar}>
        <option value="Ford">Ford</option>
        <option value="Volvo">Volvo</option>
        <option value="Fiat">Fiat</option>
      </select>
      </form>
    );
  }
}

const root = ReactDOM.createRoot(document.getElementById("root"));
root.render(<MyForm />);