> Are you thinking something like ShareDB? https://github.com/share/sharedb

Ah - I didn't have anything quite that powerful in mind, more like fairly simple, browser-local enhancements to make interacting with regular old HTML pages more pleasant. For example a drop-in library that would save the state of a form and restore it on a refresh, like the old formsaver jQuery plugin. I would like to see an ecosystem of libraries like that again