Thread:Humphry02/@comment-44975735-20200410082050/@comment-44975735-20200418133019

You need to enable personal JavaScript in your profile settings to be able to use your personal JS file.

Your solution is not working for me because the code you've posted is supposed to go into MediaWiki:ImportJS which doesn't exist at the moment because there's nothing in it. The installation guide mentions both of these things.