Board Thread:Support Requests - Getting Technical/@comment-4018164-20140426081320/@comment-11733175-20140426101746

By default, no js is imported into chat. There are two widely used methods to import it: Monchoman's chathacks, or editing mediawiki pages to insert script tags. I'm not seeing chathacks in your global.js (where people normally keep it) so I'm going to guess you're using the script tags method.

Assuming you're doing it the way described in Help:Custom Chat Javascript/CSS, you'll possibly notice that it's only importing MediaWiki:Chat.js and Special:MyPage/chat.js in terms of js. If you want it to import you're global js, you'll need to do that separately. It might be better to load the user resourceloader module (if it's available) as this will load your common and skin js file too, e.g.

I don't know how chathacks works, but judging by how Monch has claimed it to be extensible and that importing other scripts after it appears to have some effect, I would guess it loads your global.js, and possibly your local common or skin js. Without Chathacks or altering the imports as I mentioned above, you're global.js wont load.