Draft of Implementing 3.3-3.5

Proposal for 3.3 - 3.5

3.3.1 postponed for more information about the intent of this SC.  Is it 
about providing flyover information?  Or is it out of place and really 
belongs in Principle 2?

3.3.2 Location in Hierarchy
Knowing where you are in a hierarchy makes it easier to  understand and 
navigate information.  Users who are perceiving the data linearly (such 
as audio speech synthesis) do not receive visual cues of the 
hierarchical information. Efficient navigation of hierarchical 
information reduces keystrokes for people for whom keypress is 
time-consuming, tiring, or painful. For people with some cognitive 
disabilities, providing the clear hierarchy reduces cognitive effort and 
provides organization.

A media player provides a hierarchical display of playlists, albums, 
artists and songs, etc.  When the user selects an individual item, a 
breadcrumb of the categories is displayed, can be navigated and is 
available programatically.

3.3.6 (needs renumbering) Unavailable Content
Users should be given available information when a piece of content is 

Example: an image is not available either by a rendering problem, broken 
link or cannot be displayed by the device. The user agent automatically 
provides the image description, link to transcript or captions, or a 
placeholder programatically indicating the content is unavailable.

3.3.7 Retrieval Progress
Users need to know that their actions are producing results even if 
there is a time delay.  Users who cannot see visual indications need to 
have feedback indicating a time delay and have an idea of where they are 
in the retrieval process. This reduces errors and unnecessary duplicate 

The user has clicked on a link that is downloading a large file.  The 
user agent displays a programmatically available progress bar. If the 
progress stops, the user agent displays a message that it has timed out.

The user has entered data in a form and is waiting for a response from 
the server. If the response hasn't been received in 5 seconds, the user 
agent displays a programmatically available message that it is waiting 
for a response. If the process times out, the user agent displays a 
message that it has timed out.

3.4.1 Repair Missing Alternatives
When alternative content is missing, it is sometimes useful for the user 
agent to provide alternative information that is available, such as the 
filename. The user needs to be able to control the flow of this 
information, because it can be distracting and time-consuming.

Example: There is an image in web content that does not have alternative 
text provided.  The browser provides the file name because that is the 
only available information about the image.

Example: A video does not have captions. The user selects a caption 
button, and the user is informed that no captions exist.  The player 
then analizes the video soundtrack and provides speech to text 
translation served as captions.

3.4.2 Repair Empty Alternatives
When an author has chosen to code web content for alternative text but 
not provide any text information (e.g. an empty alt) the user may still 
need to know any information available about that web content.

Example: A photo sharing web site automatically generates web content 
with text alternatatives. When the photos are initially uploaded, or if 
the person posting the photos chooses not to caption that photo, an 
empty text alternative is automatically generated.  A person with visual 
impairments uploads a batch of photos and needs to know which photo is 
which in order to provide the photo description. The user agent provides 
a menu option that displays all known information about that file 
including filename and selected camera info (date, time, size, type, etc.)

3.5.1 Highlighted items  (ask Jim Allan)
Users need to be able to easily discover what web content they can 
interact with. Users with low vision need to be able to highlight 
selection, content focus, enabled elements and links (including recently 
visited links) in order to successfully discover and interact with the 
web content.

Examples: A web site uses styles to override visited link color. A low 
vision user has difficulty determining what links have yet to be 
explored.  The user agent provides a dialog box for setting overrides to 
author selected link colors.

Example: An author has created a web site with CSS styles that make 
links appear as standard text. The user agent provides a dialog box for 
setting overrides to author selected link text attributes.

3.5.2 Highlighting Options
A low vision user needs control over what visual elements work best for 
highlighting. These include foreground colors, background colors, and 
visual borders.

A low vision wants to know where the text boxes are on a web form.  The 
user wants to set a thick black border around all text boxes.  The user 
agent provides a dialog box allowing the user to override any author 

Received on Thursday, 25 February 2010 23:10:00 UTC