Current versions of SC and Definitions

• SC for viewing | SC for editing
• Change of Content definition for viewing | Change of Content definition for editing
• primary purpose of the page definition for viewing | primary purpose of the page definition for editing
• SC in full draft guideline

SC Short Name

Change of content

SC Text

Programmatic notification is provided for each change in page content unless one or more of the following is true:

1. There is a programmatically determinable relationship between the new content and the control that triggers it;
2. The user has been advised of the behavior before using the control;
3. The change in content is not a result of a user action and not related to the the primary purpose of the page.

Editor's Note for next draft: "The working group is seeking input to account for situations where there is frequent, or constant updating."

Suggested Priority Level

Level AA

Related Glossary additions or changes

• 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
• primary purpose of the page: If removed, the page would loose it's meaning or main reason for existing.

What Principle and Guideline the SC falls within

Principle: Perceivable

3.2

Description (Intent)

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. They may be working on the part of the page which is not 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"
• "content loading" (when a busy indicator is onscreen)

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
• When a graphical spinning "busy" signal notifies visual users.

Dynamic changes to a page sometimes cause the page to become inactive for a period of time while it is being updated. Users of assistive technology may think the page has crashed and may loose their work if they either reload the page or leave the page thinking the browser crashed. This notification will ensure they are aware that something is happening in the background, the way that sighted users are aware when they see a spinning icon or the words "loading". If there is no such visual indication there is no requirement in the Success Criterion to provide programmatic notification, only when there is a visual notification, is there a requirement to make that notification also programmatic. This is not about the initial wait to load a new page. Those are announced to screen readers.

Note: SC 4.1.2 covers notification of changes in content that are a result of a change in the state of a control, such as selecting a new Tab in a tabbed interface, opening and closing a menu, clicking a link or button that opens up a dialog or tooltip. The text of 4.1.2 is "... 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

Users of assistive technology will know what changed on the page, and will be able to make decisions based on that information.

Benefits

• Users who are blind will know if a shopping cart was successfully updated, or if form was successfully submitted, or if there were errors on their form.
• Helps people with visual disabilities, cognitive limitations, and motor impairments by reducing the chance that a control will be accidentally activated or action will occur unexpectedly.
• Individuals who are unable to detect changes on the page will be able to know what people who can see those changes know.

Justification and Evidence

This issue is currently a best practice recommended by most WCAG evaluators, and most evaluators have come across situations where a screen reader user became confused because something changed on the page that they were unaware of. There is a long thread on the mail archives which started here: https://lists.w3.org/Archives/Public/w3c-wai-gl/2016AprJun/0808.html. The current wording is a result of those discussions and has good momentum from working group members on the list.

There was an issue which filed against WCAG for WCAG next. See Issue 12 here https://www.w3.org/WAI/GL/wiki/Post_WCAG_2_Issues_Sorted

Testability

This can be tested programmatically or functionally. In the code, identify elements that show/hide content etc, and ensure they have programming that exposes the user to notifications about this new data. Functionally, a screen reader can be run while the page is updating to determine changes to the page are announced to the user.

Related Resources

This is also in the Pearson guideline 5 https://wps.pearsoned.com/accessibility/115/29601/7577872.cw/index.html

COGA has a similar notification SC which is a little wider currently. https://rawgit.com/w3c/coga/master/extension/rapid-and-direct-feedback.html

Techniques

• Using aria-live to notify a user of changes in content
  

possible narrowing of scope to user initiated changes

Editor note: we are seeking input about whether to limit this success criteria to user initiated changes by inserting the word "user initiated" before the word "change" and removing the last bullet.Editor note: we are seeking input about whether to limit this success criteria to user initiated changes by inserting the word "user initiated" before the word "change" and removing the last bullet.