example.js

var Form = React.createClass({
    render: function(){
        return (
            <div>
                <h3>Click the button</h3>
                <input type="submit" />
            </div>
        );
    }
});
var App = React.createClass({
    render: function(){
        return (
            <div>
                <h1> Welcome to my app!</h1>
                <Form />
            </div>
        );
    }
});
React.render(<App />,  document.getElementById("app"));