React not rendering classes on elements
<p>I currently have two files, an <code>app.js</code> and an <code>index.html</code> and when I try to render a form with some CSS classes, the HTML elements display but the classes are missing.</p>

<p>This is my <code>app.js</code>:</p>

<pre><code>var Form = React.createClass({
    handleClick: function() {
        alert('click')
    },
    render: function() {
        return (
            &lt;div&gt;
                &lt;input class='form-control' type='text' name='list-name'/&gt;
                &lt;button class="btn btn-primary" onClick={this.handleClick}&gt;Submit&lt;/button&gt;
            &lt;/div&gt;
        );
    }
});

ReactDOM.render(&lt;Form/&gt;,document.getElementById('app'));
</code></pre>

<p>This is my HTML body:</p>

<pre><code>&lt;div class="container"&gt;
    &lt;h1&gt;Title&lt;/h1&gt;
    &lt;div id="app" class="center"&gt;&lt;/div&gt;
&lt;/div&gt;
</code></pre>