I'll 2nd CouchDB for a server side solution, but you could also use PouchDB to store that data in the user's web browser. That wouldn't work when they access it

I'll 2nd CouchDB for a server side solution, but you could also use PouchDB to store that data in the user's web browser. That wouldn't work when they access it with a different browser, but that may not be a bad thing, and could be useful.