demo04/index.html

<!DOCTYPE html>
<html>
  <head>
    <meta charset="UTF-8" />
    <script src="../build/react.development.js"></script>
    <script src="../build/react-dom.development.js"></script>
    <script src="../build/babel.min.js"></script>
  </head>
  <body>
    <div id="example"></div>
    <script type="text/babel">
      class HelloMessage extends React.Component {
        render() {
          return <h1>Hello {this.props.name}</h1>;
        }
      }

      ReactDOM.render(
        <HelloMessage name="John" />,
        document.getElementById('example')
      );
    </script>
  </body>
</html>