Say Hello to Mr. DocType

[Thomas Dowling]

IE6b1 for Win32 is out <URL:http://msdn.microsoft.com/ie/>.  Its interface
doesn't change much, but there are some differences under the hood.  One
that has implications for web authors is that it joins Mozilla and IE5/Mac
in doing "DOCTYPE Sniffing."

As outlined at
<URL:http://msdn.microsoft.com/workshop/author/css/overview/CSSEnhancement
s.asp#doctype_switch>, IE6 will feature both more compliant and stricter
CSS parsing.  The strict mode is triggered depending on the presence or
absence of a DOCTYPE declaration, the version of HTML or XHTML cited, and
in some cases the presence or absence of a URL to the DTD.

This means that, if your HTML editor automatically inserts a DOCTYPE that
triggers strict mode, but your coding isn't up to snuff, your page may not
render as you expect (and as it does with IE5.5).  Conversely, if you take
pains to write your code to the letter of the specs, but don't include a
recognized DOCTYPE, IE6 may not take advantage of your work.

I'm particularly ticked that strict mode under HTML 4 Transitional not
only requires a DOCTYPE (which I mostly have) but also the URL to the DTD
at W3C (which I mostly don't).

I don't want to leave the impression that a lot of pages are going to fall
apart when IE6 hits the street.  Better standards compliance is a Good
Thing.  As far as I can see, its strict mode is limited to CSS, not HTML,
and most of the "strictures" imposed are actually corrections of things IE
has previously gotten wrong.  BUT, a number of HTML editors have a history
of applying wrong or nonsensical DOCTYPEs, or of removing any handwritten
ones, and increasingly that's going to translate into changes in page
rendering.  Worst offenders (of course): Frontpage and NS Composer.


Thomas Dowling
OhioLINK - Ohio Library and Information Network
tdowling at ohiolink.edu