>>>Ctrl+Shift+J (Error Comsole).
>>>or
>>>Tools->Web Developer->Error Console.
>>>
>>>Menu becomes available when you press Alt key.
>>
>>Thanks, I never saw the extended menu. The only think I saw so far was the Firefox orange menu on the upper left which only contains some basic features.
>
>BTW if you install "FireBug" Add-on for FireFox you will get a great debug.

Agreed. Highly recommended!