Overriding script src tag

I want to disable “adblock” detector script on shinden.pl using extension, not existing one.
The file that I need to somehow change is https://shinden.pl/f/js/main-obfuscated.js?p

To make it work i can do 3 things:

1. force aj variable to always be 0
2. delete if(p&&aj>0x0)an(bt,data);else from main-obfuscated.js
3. replace <script src="/f/js/main-obfuscated.js?p"></script> without if(p&&aj>0x0)an(bt,data);else

I searched for some examples how to do that but I couldn’t find any working solution, when i tried using one that executes code before page loads main-obfuscated.js function just didn’t want to execute but simple alert() worked.

If there is some simpler way to do it than to replace main-obfuscated.js please tell me.