React Base Fiddle (JSX)

HTML

<script src="https://unpkg.com/react@latest/umd/react.development.js"></script>
<script src="https://unpkg.com/react-dom@latest/umd/react-dom.development.js"></script>
<div id="container"></div>

Babel + JSX

class App extends React.Component {
	state = {
  	value: null,
  };

	handleChange = event =>  {
  	console.log('handleChange', event.target.value)
    this.setState({
    	value: event.target.value,
    });
  };

	render() {
  	return (
    	<div>
        <input onChange={this.handleChange} type="number" />
        <div>
          value: {this.state.value}
        </div>
    	</div>
				
    );
  }
}

ReactDOM.render(<App />, document.getElementById('container'));