How to intercept a button on a site from an extension?

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I am writing extensions for Google, this button sends a message, but I need to somehow intercept it so that my script is executed (or just change the link in the VK script), after clicking. Roughly speaking, I just need to change the code that this button executes.




I hope someone will help me, because for 4 hours I have been looking for how to do this, and the answers are only if you open the extension tab. And I need it, with VK.

Thank you very much in advance!