Best Strategy for Webkit Apps & Translation?

[maximo]

My Japanese investor wants me to make not just an English application, but a Japanese version too. (He can translate for me, he said.) So I'm just now learning these:

http://doc.qt.io/qt-5/internationalization.html
http://doc.qt.io/qt-5/qtlinguist-index.html

However, what would you recommend that I do for a Webkit widget application, where most of the content is stored in local web pages (accessed with file://) ? I guess I can traverse the Webkit bridge to be able to use the tr() statement, and then use jQuery to put the translated text in its place. However, that might run a little slow.

Another strategy, perhaps, could be that one file:// URLs pull from an "lang/en" directory inside my .app, while another "lang/jp" directory could be there for the other file:// URLs. That will run a whole lot faster unless you can think of a better idea.