W3Schools Tryit Editor

main.jsx

index.html

import { createRoot } from 'react-dom/client'

function Car() {
  const myfunc = () => {
    alert('Hello World');
  };
  return (
    <button onClick={myfunc} disabled={false}>Click me</button>
  );
}

createRoot(document.getElementById('root')).render(
  <Car />
);

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