Keeping out spammers

I would like a code to prevent people from breaking my JavaScript IP script

[Tusserte]

Hello everyone, I currently am being plagued by a spammer who wants to leave profane comments on my site for no apparent reason. He currently uses my JavaScript guestbook and forum to leave bad comments, and on those pages I was able to stall him by installing a simple redirecting JavaScript code, which was set up using SSI to make sure that it would only happen to him. He was able to get around this, however, by entering my site through a web page cache. I have since created a meta "noindex" rule on the pages, but is there any way I could keep him out until the next crawl? Thanks!

Please note that I cannot edit htaccess or use PHP at my current host; any solution will have to use JavaScript and/or SSI exclusively.

[edited by: Tusserte at 11:27 pm (utc) on Feb. 19, 2008]

[le_gber]

Presumably your redirect is IP based? If it is why not add the ip's of the cache pages as well. Record the IP he posts from and keep adding them to the list.

Alternatively, if he uses profane comments, why not block the posting if it contains a word from a list of forbidden words, that way he can only post nice things :)?