failures
failure
Content using any technology which supports keyboard interfaces.
The objective of this failure is to avoid situations in which people using a keyboard interface (e.g. tabbing through links and controls) cannot see where the indicator is due to other authored content.
Any 'sticky' content that moves with the viewport can potentially obscure other elements on the page, including controls the user may tab to.
A Web page has a sticky footer, an element that stays visible at the bottom of the viewport as the user scrolls the page. The footer is tall enough to completely cover the element in focus as a user tabs down the page.
A Web page has a sticky header, an element that stays visible at the top of the viewport as the user scrolls the page. The header is tall enough to completely cover the element in focus as a user tabs up the page.
Failure example of sticky header that completely cover elements in focus as a user tabs up the page.
Tab through the links and controls on the page. Both progressing down through the page, and back up: