is there a way to write a code to detect browser plugins?

[gizmola]

So what you are inferring is that there is no definite way of preventing users from hacking, the only possible approach is to intelligently verify each user submitted data? So assume in my script users can select their own pet ids to breed, but they can use firebug/inspect element to change the id to anything they want(even other people's pets). What I should do is to add another checkpoint to see if the selected adoptable id belongs to this specific user and returns a 'hacking attempt' message if the pet actually belongs to someone else? Is this gonna work?

 

Yes, exactly.