Here is a small Javascript. (It is a ‘smallest example’.)
<script>
var now = new Date();
var minute = now.getMinutes();
if (minute < 10) minute = "0" + minute;
document.write(now.getHours() + ":" + minute);
</script>
This throws the following error in Firefox (16.0.2):
nicht wohlgeformt
moz-nullprincipal:{356ab095-a1ae-4ba6-a22c-1df0f260f702}
if (minute < 10) minute = "0" + minute;
------------- ⬏
(“nicht wohlgeformt”: German, meaning ‘not wellformed’.)
What is the meaning of “moz-nullprincipal”. I didn’t find anything informative about that error. What’s wrong with that line?
I googled the keyword “moz-nullprincipal”, then the error occurs by Google Toolbar.
The page said you should re-install new version of Google Toolbar.