React First Component

HTML

<script src="https://fb.me/react-dom-0.14.0.min.js"></script>
<script src="https://fb.me/react-0.14.0.min.js"></script>
<div id="app">

</div>

Babel + JSX

class HelloWorldComponent extends React.Component {
  render() {
    return (      
      <h1>Discover ReactJS with</h1>      
    );
  }
}

ReactDOM.render( 
  <HelloWorldComponent/>,
  document.getElementById('app')
);