I've experimented in porting TeXmacs to Webassembly. The result is attached to this message. It is a version of TeXmacs with S7 as scheme interpreter and running with the legacy widget kit on top of a Qt layer. All compiled in Webassembly with Qt/Wasm and Emscripten. It seems usable even if compiled without optimization.
You can grab it here (67mb compressed)
but you need a local server to serve the files to the browser.
Note that this is just a test. Windows and maybe many other things are not yet working properly. You can try it safely since the program is sandboxed and cannot interact with your filesystem. In particular you have only access to a virtual filesystem in memory, so you cannot save files on your computer (yet).
Hope you enjoy. Webassembly is really an interesting technology. We should think if we can leverage it to have more widespread adoption of TeXmacs.
Max
