W3C home > Mailing lists > Public > wai-xtech@w3.org > February 2007

Thoughts about tooltips

From: Becky Gibson <Becky_Gibson@notesdev.ibm.com>
Date: Wed, 28 Feb 2007 08:12:46 -0500
To: wai-xtech@w3.org
Message-ID: <OF9BFDD212.20CEDE5A-ON85257290.004629D2-85257290.0048920A@LocalDomain>

Tooltips can be very useful but I'm not sure how to go about making them 
keyboard and screen reader accessible without being intrusive. 

Ideas:

a keyboard command to invoke tooltips and they display when mouse over the 
"trigger" element
visual indicator that a tooltip is available
Tooltips could be given the ARIA role of alert  so a screen reader will 
speak the alert when it is made visible or Tooltip can be implemented via 
the described by property on the trigger element. 

Concerns:
If the tooltip is implemented via the describedby property, screen reader 
users will hear the tooltip whenever the trigger element receives focus - 
would this be too annoying?
Is a visual indicator necessary or can the tooltip be discovered if there 
is a universal keystroke to invoke it.? 
How to implement the visual indicator?  If a small  image is used it would 
have no alt text since the tooltip is associated with the trigger element 
and is not the trigger itself.
Is is necessary to identify the existence of a tooltip for screen reader 
users?  The describedby property could be used to indicate "Press Alt-F10 
for tooltip" but I worry that could be more annoying that having the 
tooltip itself spoken via the describedby property.
Generally tooltips are displayed on a timer and then disappear.  There 
have been complaints that this makes it difficult for people with 
cognitive impairments to read. Should there be a mechanism to display 
tooltips until they are explicitly closed via escape?  Tooltips invoked 
via a certain key sequence would  remain visible until closed and mouse 
over and "standard keyboard invoked" tooltips would be  removed 
automatically.  It will be difficult to find two sequences that can be 
used to invoke alerts which do not  conflict with existing sequences. 

My inclination is to not include a visual indicator, use a keystroke to 
invoke the tooltip,  have the tooltip display on a timer, and implement 
via the ARIA alert role.  Keyboard and screen reader users would have to 
discover the tooltip by trying the keystroke sequence with focus on the 
trigger object.  Adding a second keystroke to display the tooltip until 
dismissed would be an added feature.



Becky Gibson
Web Accessibility Architect
                                                       
IBM Emerging Internet Technologies
5 Technology Park Drive
Westford, MA 01886
Voice: 978 399-6101; t/l 333-6101
Email: gibsonb@us.ibm.com
Received on Wednesday, 28 February 2007 13:12:59 GMT

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