Smarter forms in regards to ENTER key

It'd be lovely if a "smarter forms" handling in regards to the ENTER key could be added, with or without the form builder, and purely optional (of course).

By "smarter forms" I mean that ENTER in an input field quite frequently should not submit the form, but either stay in the current field, or move to the next (visible) field (or radio/checkbox) as it does with the TAB key.

(This obviously can't be done in a TEXTAREA field)

-joho