<div id="root">
    <!-- Your components contents will go here! -->
</div>
class Hello extends React.Component {
  render() {
    return (
      <div>
        <h1>Hello, world!</h1>
      </div>
    );
  }
}

ReactDOM.render(
  <Hello/>,
  document.getElementById('root')
);

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

  1. https://cdnjs.cloudflare.com/ajax/libs/react/16.7.0/umd/react.production.min.js
  2. https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.7.0/umd/react-dom.production.min.js