10. Dynamic Content

10.1 Ensuring dynamic content is accessible

Ensure that dynamic content is accessible. Provide an alternative presentation or page, and ensure that equivalents for dynamic content are updated when the dynamic content changes.

Guide to this standard

Explanation is easiest by example (as follows):

Consider a site that enables a user to shop for various products offered for sale.

The products available for selection may be presented graphically, in which case a text equivalent is also expected.

As a user selects products for purchase, the content of the shopping basket will increase. This is an example of dynamic content. The shopping basket content may be presented to the user with a graphic of each product selected (no doubt also with quantity). It would be expected to have a text equivalent with each product selected.

As an alternative, offer a non-graphic presentation version to the user.

This standard covers the W3C WAI checkpoints 6.2 (http://www.w3.org/TR/WCAG10-TECHS/#tech-dynamic-source) and 6.5 (http://www.w3.org/TR/WCAG10-TECHS/#tech-fallback-page) for NZ government agencies.

Rationale for this standard

Dynamic presentation causes problems for screen readers and other screen scanning devices, which may easily become confused with content changing dynamically.

It also presents difficulties for users with impaired vision.

It is difficult to provide meaningful alt-text for random images dynamically served to a page.

10.2 No blinking or scrolling text and flashing objects

Web pages are not to contain any blinking or scrolling text, or flashing objects.

Guide to this standard

Ensure that no items or objects on a page blink or scroll across the screen.

Related Recommendation

10.1.1 - Minimise movement in pages

This standard covers the W3C WAI checkpoints 7.1 (http://www.w3.org/TR/WCAG10-TECHS/#tech-avoid-flicker) and 7.2 (http://www.w3.org/TR/WCAG10-TECHS/#tech-avoid-blinking) for NZ government agencies.

Rationale for this standard

People with cognitive or visual disabilities may not be able to read moving text or may be distracted by it. Flashing or blinking can trigger seizures in some people.