Components delivered as part of the initial page load conform

Perceivable

Proposed SC 1.5.3

Guideline 1.5: Notification: Make it easier for users to know about changes to dynamic content.

1.5.3 Customized views: If different user interface components or different versions of the content are provided, each customized for a distinct type of device or user agent, then the content only conforms to WCAG 2.1 if:

1. Each of the different user interface components or versions of the content conforms to WCAG 2.1 or
2. A conforming alternate version is provided of each version of the content that does not conform, where the conforming alternate version is customized for the same type of device or user agent as the corresponding non-conformant version.

Proposed Understanding Document

The intent of this Success Criterion is to ensure users who have disabilities are able to use the page view that was designed for the device they are using. On responsive pages, a view of the page is usually sent to the User Agent based on the size of the screen on the device being used. User interface components, such as the menu, show/hide buttons, etc. are customized for that view.

This Success Criteria ensures that the variation of component that was sent to this device also conforms to the WCAG, without forcing the user to look for a link to a conforming alternative, which may contain a component variation that was not designed for that device.

Example

Page views created for small devices often have a menu that is made for people in a mobile environment. This Success Criterion ensures that this mobile variation of the menu meets WCAG requirements without forcing the user to find a link to the desktop view (designed for a wider screen) that contains a large complicated menu that was not designed for that device.

Additional benefits may include: the user can use the view of the page designed for their device which uses low bandwidth on their cellular connection, location services, less superfluous content, and a view oriented to the task they are trying to complete in a mobile environment.

Definition from WCAG 2 of user interface component

a part of the content that is perceived by users as a single control for a distinct function

Variation 2- from Jason

1.5.3 For each user interface component or version of the content which is customized for a specific type of user agent or device, one of the following is true.

1. The customized user interface component or version of the content conforms to WCAG 2.1, or
2. A conforming alternate version of the content, customized for the same type of device or user agent, is provided, or
3. There is no Accessibility-Supported Way of Using technologies that enables the content, as customized for the specific device or user agent, to conform to WCAG 2.1.

Jason says: the third clause is meant to address the case in which there is no (or inadequate) assistive technology support or some other lack of technology support for a particular user agent or device which makes it impossible to supply a conforming version customized for that user agent/device. Think of a platform/device type which is new enough to have no (or very little) assistive technology. Without the third clause, a customized version/UI component couldn’t be written for that platform/device, even if it’s impossible to make it conform.
Jonathan comments: As long as there is an alternative that is fine – but we need to be clear that there still must be an alternative. I agree that there will be widgets that can’t be made accessible on all devices and that we can’t force people to use the same widget across different views.