I wouldn't, but a lot of people would. From bitter experience with a project of mine, I found that quite a few poeple have javascript disabled. Also I know of at least one major corporation that has it disabled on the default browser install.

Designers/developers should never rely on a technology for site functionality, if that technology can be disabled clientside. Javascript is fine for rollovers and the like, where the site will work perfectly well without.

Louie - any chance you could PM me the location of the .der file for Firefox? I thought they only supported IE and Netscape.