This is an archived snapshot of W3C's public bugzilla bug tracker, decommissioned in April 2019. Please see the home page for more details.

Bug 6494 - Make the requiredness about alt more obvious
Summary: Make the requiredness about alt more obvious
Alias: None
Product: HTML WG
Classification: Unclassified
Component: pre-LC1 HTML5 spec (editor: Ian Hickson) (show other bugs)
Version: unspecified
Hardware: All All
: P2 normal
Target Milestone: ---
Assignee: Ian 'Hixie' Hickson
QA Contact: HTML WG Bugzilla archive list
Keywords: a11y, a11ytf, a11y_text-alt
Depends on:
Reported: 2009-01-29 15:04 UTC by Simon Pieters
Modified: 2010-10-04 13:59 UTC (History)
6 users (show)

See Also:


Description Simon Pieters 2009-01-29 15:04:19 UTC
HTML5 allows <img> elements to be associated with a "caption" by various means, in which case the alt attribute may be omitted, and AFAICT there's only one case when the alt attribute may be omitted even without a caption, which is:

" An image in an e-mail or document intended for a specific person who is known to be able to view images"

...which is probably not something that you would see on the Web and so a validator could ignore that case, making alt required (when there's no caption), meaning that a validator would flag an error when there's no alt and no caption.

From discussions on w3c-wai-pf it appears that it is not obvious from the spec that this is the case so it would perhaps be useful if the spec was clearer on this point.
Comment 1 Ian 'Hixie' Hickson 2009-04-01 01:48:45 UTC
I added a section for conformance checkers... not sure how else to do it.
Comment 2 Laura Carlson 2010-02-03 18:18:52 UTC
Please refer to the Change Proposal "Replace img guidance for conformance checkers with suggested text" [1] for details on how to modify the HTML5 Specification so that automatic validators can programmatically detect the presence or absence of text alternatives on the img element. 

Thank you.


This is associated with HTML TRACKER ISSUE-31

The full issue and is detailed at:
Omitting Short Text Alternatives on <img>
Comment 3 Michael Cooper 2010-02-11 17:17:52 UTC
The HTML Accessibility Task Force intends to track these issues, per the proposal at