JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/react/0.12.2/JSXTransformer.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/0.12.2/react.min.js"></script>
<div id="example"></div>
<script type="text/jsx">
    var Timer = React.createClass({
        getInitialState: function() {
            //Intialize component with state as 0 seconds
            return {secondsElapsed: 0};
        },
        tick: function() {
            //increment the timer and update the state
            this.setState({secondsElapsed: this.state.secondsElapsed + 1});
        },
        componentDidMount: function() {
            //Start the timer when the component is loaded in DOM
            this.interval = setInterval(this.tick, 1000);
        },
        componentWillUnmount: function() {
            //Clear the timer when the component is removed from DOM
            clearInterval(this.interval);
        },
        render: function() {
            return (
                <div>Seconds Elapsed: {this.state.secondsElapsed}</div>
            );
        }
    });

    React.render(<Timer />, document.getElementById("example"));
</script>