W3Schools Tryit Editor

main.jsx

index.html

import React from 'react';
import ReactDOM from 'react-dom/client';

const container = document.getElementById('root');
const root = ReactDOM.createRoot(container);
root.render(<p>Hello</p>);

<!doctype html>
<html lang="en">
  <body>
    <div id="root"></div>
    <script type="module" src="/src/main.jsx"></script>
  </body>
</html>