Some of the recent and upcoming changes to MediaWiki affect Javascript.
- Wikibits Javascript is gone. See ResourceLoader/Legacy_JavaScript#wikibits.js
- OOjs UI is coming soon to an editing window near you. See OOjs UI/Fixing scripts and gadgets for information on how to test your scripts.
If you're having problems with your scripts, then you can ask here for help.
Please also share this information with people at other wikis.