Accessibility Checking for Large Sites

A document’s accesskey attribute values must all be distinct. Or, to put it another way, accesskeys must not be used more than once to protect keyboard users from unpleasant surprises.

When a document’s accesskey attribute value is supplied, users can quickly activate or switch the focus to a particular element by hitting the designated key (often in tandem with the alt key). The page becomes less accessible as a result of duplicating the values for the accesskey attribute.

Make sure the value of each defined accesskey is distinct and does not interfere with any screen reader or default browser shortcut keys.

Users who must use alternative keyboards or input devices serving as keyboard emulators, users who have problems tracking a pointer, or users who are blind or have low eyesight and cannot employ eye-hand coordination-required devices like mice, cannot operate the content.

What this Accessibility Rule Checks

Makes certain that every element on the page with an accesskey attribute has a different value.

An image map consists of a single image with numerous clickable sections. Because screen readers cannot translate graphics into text, an image map, like all images, must contain alternate text for each of the distinct clickable parts, as well as for the larger image itself.

In the absence of alternate text, screen readers often announce the image’s filename. Filenames do not accurately describe images and are therefore inconvenient for screen reader users.

What this Accessibility Rule Checks

Ensures that image map area elements have alternate text.

Not all ARIA role-attribute combinations are valid. This rule ensures that each role has the required qualities.

Using ARIA attributes in roles where they are not permitted can impair web page accessibility. Using an improper role-attribute combination will have no effect on application accessibility at best and may trigger behavior that blocks accessibility for entire areas of an application at worst.

When ARIA attributes are used on HTML elements that do not conform to WAI-ARIA 1.1, they interfere with the semantics of the elements, causing assistive technology products to display nonsensical user interface (UI) information that does not represent the document’s true UI.

What this Accessibility Rule Checks

Checks that each element with an ARIA role is using only the ARIA attributes that are permitted for that role.

WAI-ARIA role attribute values must be correct. This means that values must be written correctly, correlate to existing ARIA role values, and not be abstract roles in order to properly display the element’s purpose.

When an assigned WAI-ARIA role value for the parent element is invalid, a developer’s intended accessible technology activity is disabled.

When screen readers and other assistive devices do not understand the job of each element on a web page, they cannot interact with it intelligently or explain the role to the user. When the value for a role is invalid, assistive technologies are unable to communicate the element’s features, properties, and methods. Applying role="table" to a <ul>, for example, effectively hijacks the default semantics associated with the <ul> element in a way that screenreaders do not expect, resulting in unexpected behavior.

What this Accessibility Rule Checks

Check all elements with WAI-ARIA role attribute values to confirm the role value is correct. The role value must be appropriate for the element in the context of the document.

aria-braille attributes must have a non-braille equivalent.

WAI-ARIA requires that the aria-braillelabel attribute is only ever used on elements with an accessible name, such as from aria-label. Similarly, aria-brailleroledescription is required to only ever be used on elements with aria-roledescription.

ARIA braille attributes were introduced to allow adjusting how labels and role descriptions are rendered on a braille display. They cannot be the only attribute providing a label, or a role description. When used without a corresponding label or role description ARIA says to ignore these attributes, although this may not happen consistently in screen readers and other assistive technologies.

How to Fix this Issue

• The aria-braillelabel or aria-brailleroledescription attribute may have been placed on the wrong element, such as a parent or child of the correct element. The attribute should be put on a different element.
• The element with aria-braillelabel attribute needs an aria-label attribute or other attribute that gives it an accessible name.
• The element with aria-brailleroledescription attribute needs a aria-roledescription attribute.
• The aria-braillelabel or aria-brailleroledescription attribute serves no function and should be removed.

What this Accessibility Rule Checks

Checks that aria-braillelabel is only used on elements with a non-empty label, and that aria-brailleroledescription is only used on elements with a non-empty aria-roledescription.

The destination, purpose, function, or action of an ARIA command element must be made clear in understandable text for screen reader users.

The function of items with the roles link, button, or menuitem that lack an accessible name cannot be understood by screen reader users.

What this Accessibility Rule Checks

Verifies that all elements with the roles link, button, or menuitem have a clear, understandable name.

ARIA attributes must be used as specified for the element’s role.

Using ARIA attributes on elements where they are not expected can result in unpredictable behavior for assistive technologies. This can lead to a poor user experience for people with disabilities who rely on these technologies. It is important to follow the ARIA specification to ensure that assistive technologies can properly interpret and communicate the intended meaning of the content.

Some ARIA attributes are only allowed on an element under certain conditions. Different attributes have different limitations to them:

aria-checked: This should not be used on an HTML input element with type=”checkbox”. Such elements have a checked state determined by the browser. Browsers should ignore aria-checked in this scenario. Because browsers do this inconsistently, a difference between the native checkbox state and the aria-checked value will result in differences between screen readers and other assistive technologies.

The aria-posinset, aria-setsize, aria-expanded, and aria-level attributes are conditional when used on a row. This can be either tr element, or an element with role="row". These attributes can only be used when the row is part of treegrid. When used inside a table or grid, these attributes have no function, and could result in unpredictable behavior from screen readers and other assistive technologies.

What this Accessibility Rule Checks

Check that ARIA attributes are not used in a way that their role describes authors should not, or must not do. I.e the use of this ARIA attribute is conditional.

Values assigned to ARIA role values must not be deprecated.

Using deprecated WAI-ARIA roles is bad for accessibility. They will not be recognized or correctly processed by screen readers and other assistive technologies. Using these means not everyone will be able to access essential information.

Ensure all values assigned to role="" correspond to WAI-ARIA roles that are not deprecated, or abstract. The following list indicates for each deprecated role a potential alternative that is better supported by assistive technologies:

• directory: Consider using section, list, or tree instead. Which is most appropriate depends on how directory was used.

What this Accessibility Rule Checks

Check all elements containing WAI-ARIA role attribute to ensure that the role is not deprecated in the latest version of the WAI-ARIA specification.

For screen reader users, Aria dialog items must include intelligible language that specifies the destination, purpose, function, or action in detail.

Elements with role="dialog" or role="alertdialog" that lack an accessible name cannot be understood by screen reader users.

What this Accessibility Rule Checks

Verifies that all objects with the role="dialog" or role="alertdialog" attribute have a clear, understandable name.

This rule determines whether or not aria-hidden elements contain focusable elements.

Using the property aria-hidden="true" on an element removes the element and all of its child nodes from the accessibility API, rendering the element fully unavailable to screen readers and other assistive technology.

aria-hidden may be used with extreme discretion to hide visibly displayed content from assistive technologies if the act of hiding this content is meant to enhance the experience of assistive technology users by reducing redundant or superfluous content.

If aria-hidden is employed to hide material from screen readers, the same or equal meaning and functionality must be made available to assistive technologies.

Using aria-hidden="false" on content that is a descendant of an element that is hidden using aria-hidden="true" will not reveal that content to the accessibility API, nor will it be accessible to screen readers or other assistive technology.

The rule applies to any element whose aria-hidden attribute value is true.

By adding aria-hidden="true" to an element, authors assure that assistive technologies will disregard the element. This can be used to hide aesthetic elements, such as icon typefaces, that are not intended to be read by assistive technologies.

A focusable element with aria-hidden="true" is disregarded as part of the reading order, but is still part of the focus order, making it unclear if it is visible or hidden.

What this Accessibility Rule Checks

For all user interface components, including form elements, links, and script-generated components, the name and role can be identified programmatically; user-specified states, properties, and values can be set programmatically; and user agents, including assistive technologies, are notified of changes.