MultimediaViewer is a MediaWiki extension that gives the user of a wiki a slightly nicer interface for viewing full-size, or nearly full-size, images in their browser without extraneous page loads or confusing interstitial pages. It is currently a beta feature deployed in all Wikimedia sites.

Currently it has this little problem:

Details of cross-browser fullscreen detection/switching should go into a
reusable plugin.

See this bug report for more information:
https://bugzilla.wikimedia.org/show_bug.cgi?id=56477

Please ask any questions in the bug report. You will have better chances for quicker and better answers from the project maintainers and other community contributors.

Students are required to read Wikimedia's general instructions first. Patches should be submitted to Gerrit and reference the bug report in the commit message. Improvements to an initial patch must be submitted as an amendment  to the initial patch, not as new patches.