Unfortunately the mozilla family still refuses to implement httpOnly cookies in Firefox and therefore their newest release: Firefox 2.0 still comes without support for httpOnly cookies. Luckily an annoying bug within the Firefox internals was fixed in Firefox 2.0 which enables an extension to correctly intercept incoming and outgoing cookies. In previous Firefox versions it was not possible to intercept incoming cookies, because the Cookie header was already parsed before the examine response hook was called.
Therefore I sat down during the last hours and wrote my little httpOnly extension. This extension adds transparent httpOnly cookie support to Firefox by using a funny hack.
With this little hack it is now possible to have httpOnly cookies in Firefox 2.0. You can download this little extension from here. Be warned that this was a hack of only a few hours. Therefore you should only consider it a proof of concept. However I am planning on improving it in the near future.