W3C home > Mailing lists > Public > public-html@w3.org > August 2008

Comments on the recent changes to the alt attribute section

From: Lachlan Hunt <lachlan.hunt@lachy.id.au>
Date: Mon, 04 Aug 2008 15:34:48 +0200
Message-ID: <48970578.7080407@lachy.id.au>
To: public-html <public-html@w3.org>

Hi,
   With the new draft text recently added for the alt attribute, there 
are a few cases that covered properly.  In the section describing "What 
an img element represents depends on the src attribute and the alt 
attribute", the 2nd condition states:

   "If the src  attribute is set and the alt attribute is set to a string
    with at least one character whose first character is not a U+007B
    LEFT CURLY BRACKET character ({) or whose last character is not a
    U+007D RIGHT CURLY BRACKET character (})"

With the way that's written, it's quite difficult to comprehend, and 
unnecessarily complex.  I suggest changing that condition to instead read:

   "If the src attribute is set and the alt attribute is set to anything
    else"

And then moving it down to be the 3rd condition, below these two:

   "If the src  attribute is set and the alt attribute is set to the
    empty string"
      ...

   "If the src attribute is set and the alt attribute is set to a string
    whose first character is a U+007B LEFT CURLY BRACKET character ({)
    and whose last character is a U+007D RIGHT CURLY BRACKET character
    (})"
      ...

I also suggest making the equivalent changes to the other 3 conditions 
below those, which begin with "If the src attribute is not set..."


The spec isn't clear about what alt="{}" means, nor whether or not it 
would be conforming.  It states that:

   "The string consisting of all the characters between the first and the
    last character of the value of the alt attribute gives the kind of
    image"

and then states:

   "the user agent should display some sort of indicator that the image
    is not being rendered, providing to the user the information
    regarding the kind of image that is (as derived from the alt
    attribute)"

It's not clear about what the UA should do when there is no kind given.

In IRC the other day when we discussed this proposal, you said that 
alt="{}" would probably be conforming, even though it says nothing about 
what kind of image it is.

http://krijnhoetmer.nl/irc-logs/whatwg/20080803#l-95

However, the spec isn't clear about this, since it just states:

   "In such cases, the alt attribute's value must be a description of the
    kind of image, surrounded by braces ("{" and "}")".

Either say that the kind must not be omitted (making "{}" 
non-conforming), or state that "{}" can be used when the kind of image 
is unknown.


Finally, why does the spec still allow for alt to be omitted in emails, 
instead of just requiring the email client to use alt="{attached image}" 
(or similar), when the user doesn't provide anything better?

-- 
Lachlan Hunt - Opera Software
http://lachy.id.au/
http://www.opera.com/
Received on Monday, 4 August 2008 13:35:29 UTC

This archive was generated by hypermail 2.3.1 : Monday, 29 September 2014 09:38:57 UTC