How to upload a new .js file to the site through a browser plugin?

Question

Browser extensions

I need this in order to update the old combo box (select) - make it with a search.
There is an implementation of how to convert https://itsolutionstuff.com/post/select-box-with-s...
But there is no access to the site code. Therefore, I think whether it is possible to make a plug-in for the browser, which:
1) assigns class chosen to select
2) loads external scripts
3) Calls $(".chosen").chosen();
4) Done. We get the result - select with search!

Answer 1

https://developer.chrome.com/extensions/content_sc...