[whatwg] Subsequent access to empty string URLs (Was: Base URL’s effect on an empty @src element)

[Leif Halvard Silli]

Anne van Kesteren on Wed May 1 09:46:50 PDT 2013:
> On Wed, May 1, 2013 at 5:39 PM, Boris Zbarsky wrote:
>> Interesting.  Certainly at the point when Gecko implemented the current
>> behavior I recall it matching the spec…

Thanks so much, Darin, Boris and Anne.

> Changed in: http://html5.org/r/4841
> 
> Context: 
> 
http://lists.w3.org/Archives/Public/public-whatwg-archive/2010Mar/thread.html#msg67

FOLLOW-UP on src="<empty>":

  If @src is empty (and there is no base url) a 'subsequent access' via 
a contextual menu, such as 'Show/Open image' or 'Save/Download image' 
has no effect in Firefox20, Opera12, IE10. Whereas Safari/Chrome do 
provide a contextual menu item for those features. (And the UA results 
are the same - except with regard to Firefox, also if there *is* a base 
URL.)

  Webkit/Blink seems inconsistent/buggy, right?

  A special detail is the last paragraph of section '2.5.3 Dynamic 
changes to base URLS'[1] which implies that a change to the base URL 
should (even when @src is empty, one must assume, not?) affect the @src 
URL so that a 'subsequent access' via context menu could be used to 
e.g. open the image resource set by the base URL. Is it meaningful? 

  By now, only Webkit/Blink let base URL affect the subsequent access.
  (And Firefox, but that's because of the bug.)


FOLLOW-UP w.r.t. cite="<empty>" and longdesc="<empty>":

   What if @cite or @longdesc are empty? Personally, I think it would 
be simplest to handle at least @longesc - but probably @cite too - the 
same way that @src is handled. The relevance to subsequent access to 
empty @src is that @longdesc and @cite tend, from users’ point of view, 
to be subsequently accessed (e.g. via context menu).

   Currently, the HTML spec doesn't even require the @cite attribute to 
be a *non-empty* URL - thus it can be empty.[2] By contrast, the 
@longdesc cannot be empty.[3] What is the use case for an empty @cite 
attribute?

   For @longdesc, the ‘trend’ of implementations is to ignore the 
longdesc when it is the empty string.[4] And basically, my motivation 
for these letters is to make sure that the longdesc spec can safely say 
- without conflicting with anything else - that implementations should 
ignore empty longdesc attributes.[5]

[1] 
http://www.whatwg.org/specs/web-apps/current-work/multipage/urls.html#dynamic-changes-to-base-urls
[2] 
http://www.whatwg.org/specs/web-apps/current-work/multipage/grouping-content.html#attr-blockquote-cite
[3] 
https://dvcs.w3.org/hg/html-proposals/raw-file/default/longdesc1/longdesc.html#attributes
[4] https://www.w3.org/Bugs/Public/show_bug.cgi?id=21778#c2
[5] https://www.w3.org/Bugs/Public/show_bug.cgi?id=21778#c4
-- 
leif halvard silli