But it is simple :) The underlying technology might be more complex, but the library is solid, it's trivial to update any part of the page once you have the libraries set up, and you don't need to write any javascript. Works for me!
I think you may mean easy. It may be _easy_, but it's not simple. There are so many more moving pieces, failure modes, operational issues now to consider. Websocket connections aren't free.
As someone else mentioned, SSE is a somewhat simpler protocol that achieves the same purpose. Same idea though.
Edit: SSE*
If you mean SSE, then yes that would work just as well (unless you need the bidirectionality for the client to modify some aspect of the connection after the page has loaded). There is an htmx-sse extension too.
I'm not sure how XHR alone would let you automatically get backend state changes reflected to the frontend. You can poll one or more endpoint, but that's more complicated to get right and less efficient.
Yes, that's basically the idea.
Long polling.
Check out (history of) "Comet": https://en.wikipedia.org/wiki/Comet_(programming)#Implementa...
Also writing a client ontop of an existing HTML client is very very easy so even when not on web it's east to implement...