jva

With Rails I did come up with a similar solution to Parley.js. Just add a helper that renders the needed data-attributes and you're done.

Your solution sounds nice for single page apps.

This looks more like Bootstrap to me. There is no "extending" going on, just adding some data-attributes to the markup.

At first glance, this looks like the best validation library I have seen. It so hard to find validation libs, that don't get into your way.