166313 - want tag to conditionalize HTML based on visibility of site navigation bar

Status: NEW

(Core :: CSS Parsing and Computation, enhancement, P5)

Description

[Jamie Zawinski]

I really, really like the site navigation bar: I've added LINK REL tags to all
of my photo galleries to make it possible to navigate using it.

However, I'd like to be able say "include this HTML in my document only when the
site navigation bar is not visible."  Right now, all my pages (e.g., in the URL
above) end up with two pairs of navigation links: the ones in the nav bar, and
the ones at the top of the page.  When the user has opted to enable the site nav
bar, I'd like to suppress the links in the HTML text, so allow more room for the
images.

Of course, in an ideal world, you'd get the other browser manufacturers to agree
to use this tag as well (though I don't know who else, if anyone, has a site
navigation bar.)

Comment 1

[Malcolm Rowe]

This is a fairly good idea, but I think it's more likely to be exposed through 
a psuedo-selector on CSS (':ui-supports-LINK' or similar).  You could then 
write a CSS rule to hide the HTML if the browser exposed navigation for the 
LINK element.

Reassigning to Style System.  You might get a better response if you posted to 
the w3 www-style mailing list, though.

Comment 2

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

Pseudo-classes don't seem like the right thing. 
http://www.w3.org/TR/css3-mediaqueries/ seems like a reasonable place to put UA
capabilities.  That would allow things like:

<style type="text/css" media="(link-rel-navigation)">

#navlinks {
    display: none;
}

</style>

A little clunky, perhaps, but also easily usable in a sitewide stylesheet within
@media.  (One could also query for script support.)

Comment 3

[Malcolm Rowe]

That looks much better, though Media Queries seems currently focussed on 
physical device capabilities rather than logical UA capabilities.  It's also a 
Candidate Recommendation, which I guess means that it's too late to suggest 
changes.

I guess this bug depends upon at least a partial implementation of Media 
Queries, with the addition of a new media feature (link-rel-navigation) that we 
can try to add to the Media Queries spec later.

Is there anything stopping us from doing that now? (other than doing the work, 
of course).