<div id="body"> </div>
    <script crossorigin src="https://unpkg.com/react@15/dist/react.js"></script>
<script crossorigin src="https://unpkg.com/react-dom@15/dist/react-dom.js"></script>
<script src="https://npmcdn.com/babel-core@5.8.38/browser.min.js"></script>
<script src="https://soulwire.github.io/sketch.js/js/sketch.min.js"></script>
    <script type="text/babel">

class Container extends React.Component {
  render() {
    return (
      <div id="wrapper">
      </div>
    );
  }
}
const Component = document.querySelector('#body');
ReactDOM.render(<Container />, Component);

add('#body', 'header');
add('#wrapper', 'main');

function add ( containerName, tag, content='' ){
    let tagName = document.createElement(tag);
    let container = document.querySelector(containerName);
    tagName.innerHTML = content;
    container.appendChild(tagName);
}