Success criterion 2.2.2 of Web Content Accessibility Guidelines 2.0 explicitly covers auto-updating content. Changes to a page’s content that are not user-initiated has very much been contemplated by the drafters of WCAG 2.0.
The Accessibility Barrier
The accessibility problem with auto-updating content has been two-fold:
- Auto-updating content causes the page to refresh causing a user to lose task focus. One has to re-orient oneself to the page again and navigate back to the content on the page one was reading or interacting with. This of course depends on the manner in which the auto-updating content is pushed out to the user agent.
- The alerts / updates to content are so frequent that they become an irritant for the user, again interrupting one’s task focus or ability to review or interact with content.
That’s why 2.2.2 is written the way it is:
What WCAG 2.0 mandates
Auto-updating: For any auto-updating information that (1) starts automatically and (2) is presented in parallel with other content, there is a mechanism for the user to pause, stop, or hide it or to control the frequency of the update unless the auto-updating is part of an activity where it is essential.
Note 3: Content that is updated periodically by software or that is streamed to the user agent is not required to preserve or present information that is generated or received between the initiation of the pause and resuming presentation, as this may not be technically possible, and in many situations could be misleading to do so.
Discoverability of changed content
When proper semantics and structure and role is present (by complying with other WCAG 2.0 success criteria), findability of such content is not a problem. Else, the drafters of WCAG 2.0 would not have hesitated in incorporating a specific success criterion to address it. Consider: a user is allowed to pause or turn off such updates as per SC 2.2.2. If not paused, or, on resuming the updates, one requires the ability to find these on the page which can be done if the page is properly structured. Using aria-live is one method for alerting a user of an update. Alternatively one could play a sound or incorporate an equivalent method depending on the content and situation. Then the user may choose to interrupt his task and navigate to that section to read the changed content.
A built-in example in WCAG 2.0
An example for change in content that is not user-initiated is actually built into the normative text of WCAG 2.0. One of the methods for meeting "Timing Adjustable" SC 2.2.1 states:
Extend: The user is warned before time expires and given at least 20 seconds to extend the time limit with a simple action (for example, "press the space bar"), and the user is allowed to extend the time limit at least ten times.
A time out warning is not user initiated but presented by the content. SC 2.2.1 has other requirements for time out warnings but in order to ensure the accessibility of the warning content and mechanism for extending the time limit, conformance with other success criteria of WCAG 2.0 is necessary. The dialog that contains the warning has to have a proper role and needs to grab the user’s attention and focus. Else the warning presented in text on screen will go undetected by the screen reader user.
Likewise, any other auto-updating content needs proper markup to support success criteria that apply in the situation notably Sc 1.3.1 and SC 4.1.2. Depending on its nature and situation, focus management may need to be addressed too.
Therefore, it is reasonable to conclude that compliance with WCAG 2.0 already requires content authors to incorporate techniques that permit users to identify, discover and navigate to non-user initiated auto-updateing changes in content. The Understanding WCAG 2.0 needs to be enhanced by explaining the interdependencies between success criteria. The Techniques for WCAG 2.0 too needs to be strengthened with more techniques illustrating how they can be applied to specific situations.
This topic has been referenced in a recent post, What’s The Void In WCAG 2.0 That The Proposed "Change in content" Success Criterion 3.2.6 Attempts To Bridge?