[html4all] Longdesc and data URIs

[Leif Halvard Silli]

Gallery2 is a GNU licensed PHP gallery software which (faulty) 
longdesc support.

    http://en.wikipedia.org/wiki/Gallery2

Demo page with longdesc: 
http://gallery.menalto.com/gallery/gallery-team/

However, as is evident from that same page, Gallery2 has gotten it 
wrong ... Instead of a URL, its treats the attribute as as a text 
attribute: <img src="img" alt="Bharat Mediratta" longdesc="Bharat 
with his son, Cole."/>

It is interesting to consider how Gallery2 could have improved 
their software:

    * Data URI: The text inside the longdesc attribute could be 
converted to a data URI - should be an simple conversion. Of 
course, data URIs isn't necessarily compatible with current AT 
software. However, we must expect that AT software will read data 
URIs one day.
    * same page longdesc: The longdesc texts could be moved to a 
hidden "footnote area" on the same page.
    * separate page longdesc: And of course, they could link to 
longdescs on a separate page - in the tradtional way.

I tested the data URI solution, and it works fine (via JavaScript) 
in Webkit, Opera and (I suppose) Firefox. But not in Internet 
Explorer 8 beta 2  - as Microsoft claims it is a security risk to 
support data URIs for anything but binary data.
-- 
leif halvard silli