Reveal.js is an awesome HTML Presentation Framework, that can turn your website into full-scale presentation tool – with speakers views and master/client -presentations. I have used it succesfully with WordPress in my Presenter Notes -theme for some time now.
In order to have multiplexing (master/client -presentation) to work, you need some kind of socket.io server, that transfers the keystrokes from master presentation to client-presentations. Reveal.js has its own demo socket.io server and it has been previously available in address https://reveal-js-multiplex-ccjbegmaii.now.sh/. The socket.io server is not working anymore, because of some server error. I did submitted issue about this in GitHub, but later noticed that one can deploy own socket.io server using the same service (now.sh).
In order to do that, you need to follow the instructions in https://zeit.co/now#get-started. Instead of writing your own files (
index.js, etc.), use the ones in reveal.js multiplex-plugin (https://github.com/hakimel/reveal.js/tree/master/plugin/multiplex).