On 10/06/2011 20:51, Costello, Roger L. wrote:
> Do browsers validate each XHTML document? I thought that browsers
> ignored the DOCTYPE declaration. No?
>
> Do browsers support XML Catalogs?
>
no to both, but lots of people and programs that aren't browsers process
xhtml, and lots of them might want to process the dtd, validators, xslt
stylesheets taking xhtml as input, ...
Basically browsers have a built in catalog for xhtml so they (most of
them) ignore the doctype reference URL and substitute their own dtd that
does the html entities (only), but other systems need to be more
configurable.
Just consider writing an xslt stylesheet to conver xhtml 1 to xhtml 5,
if you don't use a catalog or some equivalent redirecting entity
resolver you'll be barred after the first two conversions.
David