Last weekend my friend Steve and I did a small project for visualising Haskell function execution in the browser. It's meant to be used in education, and uses a tiny custom parser. I figured it could be of interest for anyone here learning or teaching Haskell: https://stevekrouse.github.io/hs.js/

To see it in action, scroll a bit down to the red bordered box, and click on "map", and then keep clicking on each new line.

I hope it can be useful to someone.

Cheers, JP