title: Tinymce get content
body: <p>I try to get the content of tinymce, like this:</p>
  
  <pre><code> var hallo = tinyMCE.activeEditor.getContent();
              alert(hallo);
  </code></pre>
  
  <p>but every time I get this message:</p>
  
  <pre><code>Uncaught TypeError: Cannot read property 'getContent' of null
  </code></pre>
  
  <p>I am using tinymce 4.</p>
  
  <p>Thank you</p>