Annotate Hanzi (汉字) on the page with ruby.
Excellent and a life-saver for Chinese learners! It might make your page lag/periodically freeze but if you're patient and careful enough, it won't be much of an issue.
Tried it on the Xinhua News site; broke the page very badly. Do not recommend.
Very great tool for Chinese learner.
Brendan Johnson
Referenced Expressions
https://michaelhu.net
https://pinyin.meteor.com
Aldert Vaandering
lysisius
andrew.j.alexander
charlie.li.extensiondev
Pablo Roman
Christian Schiller
Jeffrey Wang
Andrei Stanescu