title: Uncaught TypeError: React.createClass is not a function exception
body: <p>I did a html page like this</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;!DOCTYPE html&gt;
  &lt;html&gt;
    &lt;head&gt;
      &lt;meta charset="utf-8"&gt;
      &lt;title&gt;React project&lt;/title&gt;
  
      &lt;script crossorigin src="https://unpkg.com/react@16/umd/react.production.min.js"&gt;&lt;/script&gt;
      &lt;script crossorigin src="https://unpkg.com/react-dom@16/umd/react-dom.production.min.js"&gt;&lt;/script&gt;
      &lt;script src="https://unpkg.com/babel-core@5.8.38/browser.min.js"&gt;&lt;/script&gt;
    &lt;/head&gt;
    &lt;body&gt;
      &lt;div id="root"&gt;&lt;/div&gt;
      &lt;script src="react.js" type="text/babel"&gt;&lt;/script&gt;
    &lt;/body&gt;
  &lt;/html&gt;</code></pre>
  </div>
  </div>
  </p>
  
  <p>And the file react.js like this</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>var Comp1 = React.createClass({
    render: function() {
      return(
        &lt;h1&gt; Comp1 &lt;/h1&gt;
      );
    }
  });
  
  
  ReactDOM.render(
    &lt;div&gt;
      &lt;Comp1/&gt;
    &lt;/div&gt;,
    document.getElementById("root")
  );</code></pre>
  </div>
  </div>
  </p>
  
  <p>But, I got "Uncaught TypeError: React.createClass is not a function" exception, why?</p>