- From: Andrew Fedoniouk <news@terrainformatica.com>
- Date: Wed, 19 Aug 2009 15:13:27 -0700
- To: Giuseppe Bilotta <giuseppe.bilotta@gmail.com>
- CC: www-style@w3.org
Giuseppe Bilotta wrote:
> Hello all,
>
> I've recently found myself considering what kind of fallback
> capabilities current web standards offer, in case where referenced
> content is either unavailable or unsupported by user agents. The
> situation is not particularly nice, although some form of fallback
> support is being built e.g. in HTML5 with the 'source' tag for audio
> and video (although it is not being added to img, which is a pity; but
> anyway, that's for another place to discusse).
>
>
...
I am using[1] :incomplete and :busy state flags exposed to CSS.
:busy - element has active download requests to external resources (e.g.
all kind of images, document data in <frame>, etc.)
:incomplete - some of data needed for the element (list above) is not
delivered in full or one of requests has failed.
Therefore these rules:
img:busy { background-image: url(stock:activity-spin.png); }
img:not(:busy):incomplete { background-image:
url(stock:image-not-available.png); content: attr(alt); }
define what most of UAs are doing when image is not available.
In general selector :
something:not(:busy):incomplete {...}
can be used to trigger fallback rendering when some images defined by
element style are not available.
Practice shows that most of cases this is enough.
[1] http://www.terrainformatica.com/htmlayout/main.whtm
--
Andrew Fedoniouk.
http://terrainformatica.com
Received on Wednesday, 19 August 2009 22:14:11 UTC