title: Invariant Violation: _registerComponent(...): Target container is not a DOM element
body: <p>I get this error after a making trivial React example page:</p>
  
  <blockquote>
    <p>Uncaught Error: Invariant Violation: _registerComponent(...): Target container is not a DOM element.</p>
  </blockquote>
  
  <p>Here's my code:</p>
  
  <pre><code>/** @jsx React.DOM */
  'use strict';
  
  var React = require('react');
  
  var App = React.createClass({
    render() {
      return &lt;h1&gt;Yo&lt;/h1&gt;;
    }
  });
  
  React.renderComponent(&lt;App /&gt;, document.body);
  </code></pre>
  
  <p>HTML:</p>
  
  <pre><code>&lt;html&gt;
  &lt;head&gt;
    &lt;script src="/bundle.js"&gt;&lt;/script&gt;
  &lt;/head&gt;
  &lt;body&gt;
  &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>
  
  <p>What does this mean?</p>