Uncaught ReferenceError: mountNode n'est pas défini

pardonnez-moi, j'ai cherché partout et je suis nouveau dans reactjs et à essayer d'exemples. J'ai une erreur

Uncaught ReferenceError: mountNode is not defined 

Je suis l'exemple à partir d'ici http://facebook.github.io/react/tips/initial-ajax.html

et mon code ressemble à ceci

<!DOCTYPE html>
<html>
  <head>
    <title><%= title %></title>
    <link rel='stylesheet' href='/stylesheets/style.css' />
    <script src="//code.jquery.com/jquery-1.11.0.min.js"></script>
    <script src="/javascripts/reactjs/react.js"></script>
    <script src="/javascripts/reactjs/JSXTransformer.js"></script>
  </head>
  <body>
    <h1><%= title %></h1>
    <p>Welcome to <%= title %></p>
    <div id="example"></div>
    <script src="/javascripts/reactjs/build/helloworld.js"></script>
    <script type="text/jsx">
    /** @jsx React.DOM */

    var UserGist = React.createClass({
      getInitialState: function() {
        return {
          username: '',
          lastGistUrl: ''
        };
      },

      componentDidMount: function() {
        $.get(this.props.source, function(result) {
          var lastGist = result[0];
          this.setState({
            username: lastGist.owner.login,
            lastGistUrl: lastGist.html_url
          });
        }.bind(this));
      },

      render: function() {
        return (
          <div>
            {this.state.username}last gist is
            <a href={this.state.lastGistUrl}>here</a>.
          </div>
        );
      }
    });

    React.renderComponent( <UserGist source="https://api.github.com/users/octocat/gists" />, mountNode );


    </script>

  </body>
</html>

Vous en remercie d'avance!

OriginalL'auteur Hokutosei | 2014-05-12