React Base Fiddle (JSX)

Starting point for creating JSFiddles with React. This uses React with Addons.

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/babel-core/5.8.24/browser.js"></script>
<script src="https://npmcdn.com/react@latest/dist/react-with-addons.js"></script>
<script src="https://npmcdn.com/react-dom@latest/dist/react-dom.js"></script>
<script src="https://facebook.github.io/react/js/jsfiddle-integration-babel.js"></script>
<script src="https://npmcdn.com/style-it@latest/dist/style-it-standalone.js"></script>

<div id="container">
    <!-- This element's contents will be replaced with your component. -->
</div>

JavaScript 1.7

class Intro extends React.Component {
  render() {
    return (
      <Style>
        {`
          .btn-primary {
            background-color: #229ac8;
            background-image: linear-gradient(to bottom, #23a1d1, #1f90bb);
            background-repeat: repeat-x;
            border-color: #1f90bb #1f90bb #145e7a;
            color: #ffffff;
            text-shadow: 0 -1px 0 rgba(0, 0, 0, 0.25);
          }
          .btn-primary:hover, .btn-primary:active, .btn-primary.active, .btn-primary.disabled, .btn-primary[disabled] {
            background-color: #1f90bb;
            background-position: 0 -15px;
          }
        `}

        <button className="btn-primary"> Primary Button </button>
      </Style>
  	)
  }
}
ReactDOM.render(
  <Intro />,
  document.getElementById('container')
);