I tried to make a bidirectional channel from a webpage to a python script over MIDI. I'd just found that with sysex you can pack any arbitrary data that you want, that python can create virtual MIDI devices, and that Chrome can then connect to such devices.
I'm sure I'd more code than what's in my 8yo repo, but the premise is simply https://github.com/prashnts/midipacks/blob/master/midipacks/...