victorjonsson/jQuery-Form-Validator — pull request #12 by robamaton (2012-05-10 18:20:39+00:00)
Title: Optional Attribute

When you need to say "this is an optional field but if there's something there I need it validated."

I'm not sure if this fits in perfectly, but it looks like this:

Maybe there could be a setting which says "assume required" (default) or "assume optional" which could then be overridden by a data-required="true/false".

What do you think?