[whatwg] alt and title attribute exception

[Steve Faulkner]

Hi all,

The spec currently allows img without alt if the title attribute is present

This is problematic for a number of reasons:

1. One of the functions of alt as implemented is that the text is displayed
when images are disabled or not available . I ran some tests a while
back[1] and found that while webkit based browsers display title attribute
content if images are disabled or not available, IE, Firefox and Opera do
not. I did a quick recheck and focund the implementations have not changed
in the 2.5 years since I ran those tests.

2. title attribute content is commonly displayed as a tooltip that appears
when a user moves their mouse over an element (in this case an img) It is
long running issue (14 years or so) that tooltips and thus title attribute
content is not displayed for keyboard only users. Browsers vendors are
fully aware of the issue, but as yet there have not yet been moves to fix
the issue*


It is suggested that due to the current and historical implementation of
title attribute display in browser, discouraging authors from using the
<img title="text"> markup pattern would result in more usable and
accessible content.

We could address this problem by making changes along these lines:

Remove the clause in the spec [2] that makes the markup pattern conforming:

"The title attribute is present and has a non-empty value"


If at some point in the future browsers implementations change to:

1. Displaying title attribute content when images are disabled or are not
available.
2. Providing input device independent access to title attribute content on
non focusable elements.

It would then make sense to reapply the clause so that the spec and
implementation realities align.


* IE 10 has implemented the display of tooltips on focusable elements, but
this does not resolve the issue for non focusable elements.

Note: further details of the issues are available [3]

[1] http://www.paciellogroup.com/blog/misc/HTML5/alt-tests/alt-examples.html
[2]
http://www.whatwg.org/specs/web-apps/current-work/multipage//embedded-content-1.html#guidance-for-conformance-checkers
[3] http://www.w3.org/html/wg/wiki/ChangeProposals/notitlev2

-- 
with regards

Steve Faulkner
Technical Director - TPG

www.paciellogroup.com | www.HTML5accessibility.com |
www.twitter.com/stevefaulkner
HTML5: Techniques for providing useful text alternatives -
dev.w3.org/html5/alt-techniques/
Web Accessibility Toolbar - www.paciellogroup.com/resources/wat-ie-about.html