Re: XHTML question fest

James Tauber (
Fri, 23 Jul 1999 23:45:54 +0800

> * Is XHTML a *strict* subset of HTML>

No. At least not in the sense of a language being a subset of another if all
valid strings in one are valid in the other. The principal example that
comes to mind is empty elements which look different between XHTML and HTML.

> * Are their translations so HTML style sheets can be trivially recast as
> XHTML style sheets? Is this the same as CSS -> XSL? Or am I using
> terminology again?

I would imagine stylesheets written for HTML would work without modification
with XHTML.

> * Will XHTML be 'properly' rendered by:
> - normal HTML browsers (to the limit of the mappings)

There are some issues with regard to correct processing of empty element
tags. Some browsers aren't happy with <BR/> but are willing to take <BR />
or <BR class="hack"/>

> - any XML-capable browser (that understands the concept of HTML)

An XML-capable browser that supports stylesheets would enable you to produce
the behaviour and presentation of HTML that way. A hybrid like IE5 should
handle it.

> * If I'm writing XHTML, which form should I use to be conservative?

Depends on how much you care about appearance on browsers that don't support
CSS (or don't support it properly, which is basically everything!). I always
try to use Strict + CSS, but will confess (as I have done before on FoRK) to
still using tables for layout because of not enough support for CSS.

> - If I'm writing HTML, should I start writing XHTML instead? Why or
> not?

You should probably start writing XHTML. If you spend enough time
hand-authoring XML, you'll probably find yourself writing your HTML as XHTML
anyway. The only thing I think you need to watch for are empty element tags,
but as I indicated above, I think <BR /> or <BR class="hack"/> covers most

> * Does IE5 'really' support XHTML? Does anyone? Are people going to
> it into web design tools (a la HTML/FrontPage) or into structured document
> tools (a la SGML/Framemaker)?

I don't know, to be honest.

> * Is this really intended/going to replace HTML, or is it just a way to
> rationalize the pseudo-HTML efforts people (like the cell phone folks) are
> working on?

I think it's the next step in the evolution of HTML, albeit a small one. The
real benefits will come with modularisation and the appearance of additional
modules. XHTML as it currently stands is just a prolegomenon to that work.

> Inquiring minds want to know. The truth is out there... on FoRK.

Of course!

James Tauber