To clarify, it won't work if you are accessing using the mobile app or the mobile web version. Similar to how you can't edit when through those methods either. However, if you use your phone's web browser and ask specifically ask for the desktop version, everything should work fine; JS and all. Well, except I recently found out Wikia goes out of their way to intentionally disable the wiki background image on small devices. However, other than that, I haven't seen any other differences between accessing via desktop and accessing via phone requesting the desktop version.
If you use your mobile browser and ask for desktop mode, you should be able to edit similar to how you would on an actual desktop. If your mobile device doesn't allow you to copy-and-paste, then try to get access to a desktop/laptop. If your phone doesn't need to refresh pages each time you open a new tab, you can try opening both the source and destination pages at the same time and then switching back and forth as needed to manually copy the content. Last resort would be to temporarily give one of us admin status on your wiki; but I wouldn't advise it.
Oh, okay. Well then the issue isn't that you can't copy-and-paste things. The issue is that you don't have the permissions necessary to import the script. Consider asking an admin to import the script.