That's a good question.
I was ready to reply that an EMPTY element must have nothing between
the start- and end-tags, but that's not immediately clear upon reading
the spec.
Validity Constraint: Element Valid
An element is valid if there is a declaration matching elementdecl
where the Name matches the element type, and one of the following
holds:
1. The declaration matches EMPTY and the element has no content.
but it's not clear whether "no content" prohibits ignorable
whitespace.
-Chris
-- <!NOTATION SGML.Geek PUBLIC "-//Anonymous//NOTATION SGML Geek//EN"> <!ENTITY crism PUBLIC "-//O'Reilly//NONSGML Christopher R. Maden//EN" "<URL>http://www.oreilly.com/people/staff/crism/ <TEL>+1.617.499.7487 <USMAIL>90 Sherman Street, Cambridge, MA 02140 USA" NDATA SGML.Geek>