How the server fires the execution of user js How to deal with this?

Question

Bots

In general, there is a browser toy. through the executable js file (bot) actions are performed. with random time between clicks. The clicks specified in the js file are executed.
If we use this file, we get a ban. and two minutes later automatically. If we do not use and play with our hands, we perform the same actions that our js performs, we do not get a ban. thousands of people do the same.
Actually the question is:
1. how the system in this case, the site, for its part, determines the use of the script. Determines automatically.
2. how to deal with it.
3. Is there anything similar besides using the executing js method?
The js executable is the regular js code in the js file. Installed in the settings of any browser. and then performs the actions specified in it.
example file for the game vten.ru