Proposed SC on information added or removed from a page
- 1 SC Shortname
- 2 SC Text
- 3 Suggested Priority Level
- 4 Related Glossary additions or changes
- 5 What Principle and Guideline the SC falls within
- 6 Description (Intent)
- 7 boneyard
Change of content:
Programmatic notification is provided for each change in content that indicates an action was taken or that conveys information, unless one or more of the following is true:
- The change immediately follows the control that triggered it, in the programmatic reading order.
- There is an accessibility supported programmatic relationship between the new content and the user activated control that triggers it.
Suggested Priority Level
Related Glossary additions or changes
- Programmatic notification: Notification by software from data provided in a user-agent-supported manner such that the user agents can extract and present this notification to users in different modalities, without further action by the user, except for focusing on the control which caused the change, or activating the control which caused the change.
- Change of content: Changes made to a web page after it has been delivered to the user agent, whether or not initiated by the user.
- Programmatic Reading Order: The order that a reading device such as a screen reader parses the content.
- Note: Usually, this is the same order as the code, and is represented as an accessibility tree.
What Principle and Guideline the SC falls within
Proposed new Guideline 1.5: Notification: Make it easier for users to know about changes to dynamic content
This Success Criteria is intended to help users of assistive technology be aware of changes that many users can easily see and understand. There are a number of cases where content changes on a page after it is loaded. Users who are blind or have low vision that rely on a screen reader may have trouble knowing that information on a page changed. For blind users they are working in the part of the page that has focus or the virtual cursor. This may not be near where changes have occurred on a page. It may be on a part of the web page that they have already read and wouldn't consider reviewing that part of the page for unannounced changes. These messages would be very short in nature, such as:
- "Your shopping cart has been updated, 5 items"
- "Your form was successfully submitted."
- "There are 5 results for your search"
- "There are 3 errors on this form"
- "Scores updated"
Examples of situations where this type of notification would be appropriate include:
- Interactive controls may change the page based on a users selection
- filter / sort selections of data already displayed on page add/remove content
- additions and subtractions to/from a cart
- a notification that 'support by chat' is available for this task at hand, or
- results of form submission when they are displayed on same page
- a global error message placed above the form saying "form submission failed etc." or a thank you message after completion of a multi-step process,
- on switching from grid view to list view,
- in data table when sort column is changed,
- on selecting a different pagination link
There are a number of situations where notification of changes in content can be provided by reporting the change in state of a control. These include: change in content as a result of a user selecting Tab C instead of Tab A or opening / closing a menu, or clicking a link or button that opens up a dialog or tooltip. These are all covered in 4.1.2 which says "... states, properties, and values that can be set by the user can be programmatically set; and notification of changes to these items is available to user agents, including assistive technologies."
Specific Benefits of Success Criterion 1.5.1
- Users Users who are blind will know what changed on the page, and will be able to make decisions based on that information.
Resources are for information purposes only, no endorsement implied.
Techniques and Failures for Success Criterion 1.5.1
The main technique is <aria-live>,
Using aria-live to notify a user of changes in content
Removed third exemption:
SC 1.5.2 Loading/Busy: After initial page load, programmatic notification is provided for each visual indicator that content is loading or the page is busy (Level AA)
- The primary purpose of the web page is to provide real time updates where there are more than [x] update(s) a minute.
- Changes in orientation can cause some content on the page to be added or removed, or changed.
- Responsive pages may provide different views and content might drop off
aria-describedby technique on the activating button in the case of advance notification.
Adding/Removing content: User is notified of additions and deletions, except where an interactive control that made the change(s) precedes these changes in the accessibility hierarchy. <p>NOTE: we need to define accessibility hierarchy. Perhaps something like this:Accessibility hierarchy: The order that content is presented to assistive technology. In many technologies, this is defined as the Accessibility Tree.