windows 7 OK
https://codepen.io/gaearon/pen/rrpgNB?editors=1010
https://facebook.github.io/react/docs/rendering-elements.html#rendering-an-element-into-the-dom
Applications built with just React usually have a single root DOM node. If you are integrating React into an existing app, you may have as many isolated root DOM nodes as you like.
https://medium.com/@ericclemmons/react-event-preventdefault-78c28c950e46
https://facebook.github.io/react/docs/events.html
event.preventDefault();
// Let's stop this event.