Hello,
MediaWiki has JavaScript code conventions which is enforced on core and some extensions by running jshint in Jenkins:
http://www.mediawiki.org/wiki/CC/JS
Unfortunately lot of extensions do not match that expectation yet and it would be rather nice to bring them on par.
We have a tracking bug listing some repositories which are not passing jshint yet:
https://bugzilla.wikimedia.org/show_bug.cgi?id=60619
It would be rather nice to have all extensions fixed :-]