Currently there are various contrib modules implementing form validation and/or submission via AJAX/AHAH.
Recently the Ajax forms module was written. Ajax forms provides functionality similar to that of the D5 Ajax submit and an API similar to that of the D6 Ajax submit.
Besides this, many modules implement one or another custom approach to AJAX form submission, e.g., Views.
The proliferation of contrib implementations of AJAX/AHAH form validation and submission suggests two needs:
Standardization on a common API to be jointly developed and maintained.
Consideration of introducing AJAX/AHAH form validation and submission to Drupal core.
This post is an invitation to discussion of these topics.
Is there interest in working up a core patch introducing AJAX form validation and submission? If so, what are our best starting places? What is our best approach for D6?
(I recently posted an enabling issue that might help remove an obstacle to AJAX submission in core: http://drupal.org/node/357336.)