SOURCE

const Hello = React.createClass({
    render: function() {
    	return <div>Hello {this.props.name}</div>;
    }
})

const First = React.createClass({
    render() {
        return <div>hello {this.props.name}</div>
    }
})

const root = document.getElementById('app')
// ReactDOM.render(
//   <h1>hello world</h1>,
//   root
// );

ReactDOM.render(
  <First name="World" />,
  root
);

<script src="https://cdn.bootcss.com/react/15.5.4/react.min.js"></script>
<script src="https://cdn.bootcss.com/react/15.5.4/react-dom.min.js"></script>

<div id="app"></div>