Online Tool to Validate Compound XHTML Documents

Hi Folks,

Modern Web design says that it's best practice to validate your XHTML
document before publishing them online.  The W3C validator tool can be
used to validate XHTML documents:
http://validator.w3.org/ 

An XHTML document may have embedded SVG, how do you validate both the
XHTML and the SVG?

An XHTML document may have embedded MathML, how do you validate both
the XHTML and the MathML?

Jirka Kosek has created an online tool that can validate such compound
documents:

http://relaxed.vse.cz/nextgeneration/

NVDL is used to validate these compound documents.  Here are the NVDL
meta-schemas:

http://relaxed.cvs.sourceforge.net/relaxed/relaxed_nvdl/schema/xhtml/1.
0/


/Roger