to my forum? The 403 error appears. I don't know why you guys block html and javascript when all websites uses it and webmaster add html and java to their websites lol.
This would be mod_security2. The rules set primarily attempts to protect sites from certain user input.
This in most cases won't trigger a 403 for HTML or JavaScript if they were to be added into the actual file or outputted (from the database) unless seen as a suspicious pattern (AKA what an attacker might input).