Full example

var ExampleApplication = React.createClass({
    render: function() {
      var elapsed = Math.round(this.props.elapsed  / 100);
      var seconds = elapsed / 10 + (elapsed % 10 ? '' : '.0' );
      var message =
        'React has been successfully running for ' + seconds + ' seconds.';

      return <p>{message}</p>;
    }
  });
  var start = new Date().getTime();
  setInterval(function() {
    React.render(
      <ExampleApplication elapsed={new Date().getTime() - start} />,
      document.getElementById('container')
    );
  }, 50);