JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://unpkg.com/react@15/dist/react.js"></script>
<script src="https://unpkg.com/react-dom@15/dist/react-dom.js"></script>
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.7/css/bootstrap.css">
<h1>Here is your Counter:</h1>
<app></app>

Babel + JSX

class Counter extends React.Component {
	constructor() {
  	super();
    
  	this.state = {
    	count: 0,
    }
  }
  
  increaseCount() {
  	this.setState({ count: this.state.count+1 })
  }
  
  componentWillMount() {
  	setInterval(this.increaseCount.bind(this), 1000);
  }
  
  render() {
  	return <h1>{this.state.count}</h1>
  }
}

ReactDOM.render(
	<Counter />,
  document.querySelector("app")
);