[eluser]Holla die Waldfee[/eluser]
After all it is really important to mention that FIREBUG is "Javascriptcoders best friend" ;-)
Do not try it without it! If anyone did not like Firefox (which is mandatory for the use of Firebug) he can try to user CompanionJS for IE. But it is painful to install and has not the power of Firebug!