Schemas to validate data input

[David Wall <d....@computer.org>]

Is it feasible to use XML Schemas to validate data entry forms?  For
example, I have an XSLT stylesheet that creates an HTML input form.  The
user fills out the form, clicks submit, but then my program needs to
validate the data.  One solution would be simply to convert the POST data
into a simple XML doc and have a corresponding schema that defines many
validations.  This way, I wouldn't have to define regex/min/max/etc in the
validation bean, I could just pass it to the schema-based checker.  Then I
could return the XML data with the linked schema back to the web browser for
subsequent display.

Is this really possible?  Can XML Schema tell me WHICH field(s) are invalid
so that I could display an error message back to the user and flag that
field so the user would know which field was in error and why?  Or do I have
to wait for XFORMS to be viable to do this sort of thing?

Thanks,
David