Web headers

[Joe Buck]

Zack writes:

> No one's done validation on all the existing web pages to make sure
> they are correct XHTML.

Gerald has done some validation, but to really have correct XHTML the
DOCTYPE should be present.

> Browsers seem to be happy with XHTML <tag />
> notation in a document marked as plain HTML, but they may not accept
> the other way around.

The space between the tag and the / is what makes the backward
compatibility work: the older browsers just ignore the / as an
unknown pseudo-attribute.  XML would allow the writing of <tag/>.

As best I can tell, browsers have always completely ignored headers
they don't understand, and this was a widely understood design principle
of the web going back to pre-Mosaic days.

> Also, I believe there were concerns about browsers giving up
> completely when faced with a DOCTYPE they didn't understand, or the
> required <?xml ...?> header.

I would be amazed if such a browser existed.  Browsers have never
worked that way; they keep lumbering on, trying to do something
sensible in the presence of the most bletcherous error-filled "HTML";
they do so by ignoring what they don't understand, but still processing
any data between <mystery-directive> and </mystery-directive>.

> [myself, I'd be quite happy to see us go whole hog for strict XHTML
> and style sheeting.]

This, on the other hand, is more likely to cause problems: if all of the
style is in the style sheet, that's more likely to cause problems for
Netscape 4.x.  I would recommend only going for "XHMTL 1.0 Transitional".

> zw
>