In-Browser Cryptomator - different approach


I’ve read that a (partial?) JavaScript implementation of Cryptomator was considered, so that the cryptographic functions could be used by a web app running in the browser. I don’t know what came of that idea, but perhaps there is an easier way:

I’ve come across JavaPoly, which is basically polyfilling native JVM support in the browser. It is based on doppio, which is a JVM written in TypeScript. So using that I should be able to load in a .jar file the same way I load a .js library - by using a <script> tag in the HTML. Once loaded, I should be able to call the public APIs contained therein.

Has anyone ever tried a scheme like that? Does it seem feasible?