RE: Opera 9.5 and document() function

Note that it's entirely conformant (and sometimes even useful) for an
implementation of document() to reject every URI you throw at it as "not
recognized" or "inaccessible". It's not conformant, however, to fail to
provide the function.

Interoperability and marketability, of course, demand rather more than mere
conformance.

Michael Kay
http://www.saxonica.com/