is there an easy way to check if a user bypassed the client-side input validation? Thought about this as a security measure to ban everybody trying to bypass validation. However every solution i came up with during the last days (e.g. storing input-parameters in objects or as arrays) turned out really overcomplicated and confusing.

So before I go insane trying to find a clean solution I decided to ask for some help since I'm pretty new to PHP.
Maybe it's pointless to do so anyways.