It would be cool if they made a client side version of this using Emscripten.
Theoretically it should be possible as Emscripten actually converts LLVM bytecode to Javascript, and you seem to be able to convert Java bytecode to LLVM bytecode, but Emscripten's [portability guidelines](http://kripken.github.io/emscripten-site/docs/porting/guidel...) seem to say that you cannot compile multithreaded code, which I assume LibreOffice does use...