I have spent most of my waking moments this weekend coding, refactoring and documenting a framework for easily extensible unobtrusive client-side form validation.
XUI Validation is based on jQuery and provides a simple mechanism for adding new custom validations that will apply via unobtrusive semantic hooks to any form.
Why another unobtrusive validation framework? Because the other OSS validation frameworks I have come across are not as easily extensible, or provide the ability to display a summary of errors a the top of the form (on submit).
Thoughts, ideas, feedback? Leave me a comment.