Besides the well-known basic permissions, like hiding toolbars or raise or lower windows, with Controle de Scripts you can set what functions or properties each site can access or modify, thanks to its Security Policies implementation.
Controle de Scripts is Mozilla Firefox, SeaMonkey, Flock and Netscape Navigator compatible and is available on many languages.
Firefox (or derived):
SeaMonkey (or derived):
Preferences window > Advanced > Scripts & Plug-ins