If you browse JLSE on HTTPS, the furigana JS doesn't load.
This is because the furigana JS is served as http://sstatic.net/js/third-party/japanese-l-u.js?v=6
instead of as https:// ...
Since sstatic.net
seems to support HTTPS just fine, I think this should probably not be too difficult to fix for whoever is responsible for these sort of things.