igor0
2
Well, the question doesn’t stand whether it is needed, I’m afraid - but rather if it can be done at all. Even for IE and Netscape, Script Blocking is quite a big hack - and Opera has a monolitic design that doesn’t make this kind of tricks possible 
This answers the first question as well - even though Firefox may originate from Mozilla, there has been some changes probably; therefore, the Mozilla Script Blocker module won’t work here.