No keyboard trap non-standard navigation
This rule checks if it is possible to use non-standard keyboard navigation to navigate through content where focus is trapped when using standard ways of keyboard navigation.
Note: This rule only applies to HTML and SVG. Thus, it is a partial check for WCAG 2.0 success criterion 2.1.2, which applies to all content.
Note: As per WCAG 2.0 Success Criterion 2.1.1 Keyboard the help information should be accessible through a keyboard interface.
The help information explains how to cycle to the browser UI, or on how to get to a point from where it is possible to cycle to the browser UI, using standard keyboard navigation.
For each target element focus can cycle to the browser UI by using the method advised in the help information.
Note: Cycling back to the browser UI can be done both by moving forward through the tab order and by moving backwards. It is not possible to fulfil this expectation by using browser specific shortcuts to return to the browser UI.
There are no major accessibility support issues known for this rule.
Keyboard trap with help information in a paragraph before, and where the method advised works.
Keyboard trap with help information within the trap, and where the method advised works.
Keyboard trap with “help” link that once clicked exposes the instructions.
Keyboard trap with no instructions.
Keyboard trap with instructions that doesn’t give advise on the method for proceeding.
Keyboard trap with help text, where the method advised doesn’t work.
Not a keyboard trap (interactive element).
Elements that can become the target of keyboard input as described in https://www.w3.org/TR/html/editing.html#focusable and https://www.w3.org/TR/html/editing.html#can-be-focused.
Standard keyboard navigation entails using one or more of the following:
Expected behaviour of standard keyboard navigation keys:
Elements included in the accessibility tree of platform specific accessibility APIs. Elements in the accessibility tree are exposed to assistive technologies, allowing users to interact with the elements in a way that meet the requirements of the individual user.
The general rules for when elements are included in the accessibility tree are defined in the core accessibility API mappings. For native markup languages, such as HTML and SVG, additional rules for when elements are [included in the accessibility tree] can be found in the HTML accessibility API mappings and the SVG accessibility API mappings.
Note: Users of assistive technologies might still be able to interact with elements that are not included in the accessibility tree. An example of this is a focusable element with an
aria-hiddenattribute with a value of
true. Such an element could still be interacted with using sequential keyboard navigation regardless of the assistive technologies used, even though the element would not be included in the accessibility tree.
Elements should be visible on the page, and also meet the requirements for color contrast and visibility when focused. For more details, check out:
Content perceivable through sight.
Content is considered visible if making it fully transparent would result in a difference in the pixels rendered for any part of the document that is currently within the viewport or can be brought into the viewport via scrolling.
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