Style Sheets (was: lynx-dev Old timer ? (was too long))

[David Woolley]

>  
> > o full style sheet handling not yet handled
> >   and limited style sheet handling still not consistently handled.
> 
> another of the many gaps in my knowledge: what's a style sheet?
> hence, another thing i've never had any need for.

If used properly (and they are often used just for gimmicks) style sheets
is the one web development that could actually help Lynx.

Amongst other things:

 - instead of littering the HTML with font directives, you establish
   classes of text and identify those, then describe the font characteristics
   separately, possibly even in a single, house style, document for the whole
   site (problem needs people to think about the structure of what they are
   writing) (works on MSIE 3, 4 and NS4, at least) - if nothing else this
   can greatly reduce the size of a page;

- instead of ignoring list structures and simply using IMG and P to get your
  flowery bullet point symbol, you use real list structures then provide 
  instructions in the style sheet that tell a CSS aware browser (this one works
  on MSIE 4, but not NS 4.05 - falls back to a simple bullet point on earlier
  browsers and Lynx) - this means that automated tools can again recover the
  true stucture of a document;

- instead of arguing whether H1 should be centered, you simply supply a style
  sheet that declares your personal preference (MSIE 3, 4, and NS4, I think);

- instead of having a mass of frames++, you put your banner and menu into DIVs 
  and absolutely position them with the style sheet - earlier browsers
  show them in sequence, so you get frame and non-frame structures with
  no duplication of HTML (MSIE 4, and partially in NS 4.05).

Moreover, although not currently well supported, the user can provide his
own style sheets (this is supported for NS, I think) and indicate that
certain parts should override any style supplied with the document (this
is rather less well supported).  In particular, the latest style sheet spec
allows one to provide styles, either from the server or as a local override,
with special rules for speech presentation, or printing.

One difficulty is that style sheets only work well if the HTML is 
valid, as styles generally apply to a subtree in the parsed document.  
Also there seems not to be any style sheet support in the popular authoring
tools.

Note that some aspects of style sheets shouldn't be implemented in Lynx,
e.g. absolute positioning probably doesn't make sense - the real benefit is
that well designed pages can fall back gracefully without having to have
multiple versions of the page.  Lynx probably wants to implement !important
(overriding style) and may need to have a !!!important, to override abuses
of !important!

++My impression is that the general move is towards eliminating frames,
although absolute positioning is not enough, and the use of object for
selectable content will still give Lynx problems if people don't provide
sensible alternatives ("Your browser doesn't support objects - we're not
prepared to talk to you unless you get this one that does").