title: What means moz-nullprincipal?
body: <p>Here is a small Javascript. (It is a ‘smallest example’.)</p>
  
  <pre><code>&lt;script&gt;
      var now = new Date();
      var minute = now.getMinutes();
      if (minute &lt; 10) minute = "0" + minute;
      document.write(now.getHours() + ":" + minute);
  &lt;/script&gt;
  </code></pre>
  
  <p>This throws the following error in Firefox (16.0.2):</p>
  
  <pre><code>nicht wohlgeformt
  moz-nullprincipal:{356ab095-a1ae-4ba6-a22c-1df0f260f702}
   if (minute &lt; 10) minute = "0" + minute;
  ------------- ⬏
  </code></pre>
  
  <p>(“nicht wohlgeformt”: German, meaning ‘not wellformed’.)</p>
  
  <p>What is the meaning of “moz-nullprincipal”. I didn’t find anything informative about that error. What’s wrong with that line?</p>