That would depend on the forum. Do you mean the restricted content is in js, or the authentication form is in js, or a js frame allows you to view restricted content... etc. You may find that learning a bit about javascript injections might answer your question. If it's simply bypassing authentication that you want, you can check out some techniques for that and get some hands-on practice at hackthissite.org. Sorry I can't give you a more specific answer, but without seeing the site, I don't really know exactly what you're asking for. And no, that was not a request for you to send me the site because I think that's against the forum rules. But the more information you could give about it and what you're trying to do, the more information I can give you about it.