Accessibility Checking for Large Sites

Some ARIA parent role values must contain specific child elements and role values in order to execute the intended accessibility function.

WAI-ARIA outlines specifically, for each role, which child and parent roles are permitted and/or required. ARIA roles lacking needed child roles will not be able to execute the desired accessibility functions.

The user’s context must be communicated by assistive technology. In a treeitem, for instance, it is essential to know the parent (container), item, and siblings in the folder. This is possible in two ways:

• Code order or DOM: The context required is frequently evident from the code order or DOM.
• ARIA: ARIA (such as aria-owns) can be used to provide relationships when the hierarchy differs from the code structure or the DOM tree.

What this Accessibility Rule Checks

Checks each element containing a WAI-ARIA role for the presence of all requisite child roles.

Certain ARIA roles must be enclosed by specific parent roles in order to carry out their intended accessibility functions.

WAI-ARIA outlines specifically, for each role, which child and parent roles are permitted and/or required. Elements with ARIA role values that lack needed parent element role values will prevent assistive technology from functioning as the developer intended.

When it is necessary to convey context to a user of assistive technology in the form of hierarchy (for example, the importance of a parent container, item, or sibling in a folder tree), and the hierarchy is not the same as the code structure or DOM tree, it is impossible to provide relationship information without using ARIA role parent elements.

What this Accessibility Rule Checks

Checks each WAI-ARIA role-containing element to confirm that all required parent roles are present.

Ensures that the aria-roledescription attribute is only applied to elements having explicit or implicit role values.

Inappropriate aria-roledescription attribute values that clash with an element’s implicit or explicit role value can impede the web page’s accessibility. A contradictory aria-roledescription attribute value may have no effect on the application’s accessibility and may trigger behavior that blocks accessibility for entire application sections.

When aria-roledescription attributes are applied to HTML elements not in accordance with WAI-ARIA 1.1, a semantic conflict may occur between the aria-roledescription value and the implicit or explicit element role value, resulting in assistive technology products reporting nonsensical user interface (UI) information that does not accurately represent the intended UI experience.

What this Accessibility Rule Checks

Use aria-roledescription values to adequately explain implicit or explicit element role values.

ARIA role values must be assigned valid values. Role values must be appropriately written, correlate to existing ARIA role values, and not be abstract roles in order to correctly display the element’s purpose.

Assistive technologies do not read elements with erroneous ARIA role values as intended by the developer.

When screen readers and other assistive devices do not know the function of each element on a web page, they are unable to interact with or communicate the function to the user. When a role value is invalid, an element’s characteristics, properties, and ways of transmitting information to and/or from the user can be communicated via assistive technologies.

What this Accessibility Rule Checks

Examines each element containing the WAI-ARIA role property to check that its value is valid.

Makes certain that each ARIA toggle field has an accessible name.

Ensures that any element having a semantic role has a name that is easily accessible.

Among the semantic roles are:

• checkbox
• menu
• menuitemcheckbox
• menuitemradio
• radio
• radiogroup
• switch

What this Accessibility Rule Checks

There is an accessible name for ARIA toggle fields.

Valid values must be present for ARIA properties that begin with aria-.

To fulfill the intended accessibility purpose, these values must be written correctly and relate to values that make sense for a certain property.

ARIA attributes (those beginning with aria-) must have legitimate values. For a given attribute to fulfill the intended accessibility function, these values must be written correctly and correlate to values that make sense.

A diverse range of values are accepted for many ARIA attributes. There must be permitted values, acceptable “undefined” values, and acceptable “default” values.

Content that does not adhere to the permitted values is inaccessible to users of assistive technology.

What this Accessibility Rule Checks

Verifies that the WAI-ARIA attributes’ values are correct for each element that contains them.

The names of ARIA attributes beginning with “aria-“ must be correct.

A reference to an invalid attribute or an attribute that doesn’t exist will result in a violation of this rule.

The accessibility function intended by the developer will not be fulfilled if the developer uses an invalid or misspelled ARIA attribute.

User interface components meant to increase the accessibility and interoperability of web and application content must adhere to properly worded and up-to-date ARIA properties in order for assistive technology to provide suitable information to people with disabilities.

Insufficient usage of the WAI-ARIA 1.1 W3C Recommendation’s attributes prevents developers from correctly communicating user interface actions and structural information to assistive technology in document-level markup.

What this Accessibility Rule Checks

Verifies that all elements that contain WAI-ARIA attributes have those attributes and that they are legitimate attributes.

Make sure that the kind attribute in the track element is set to captions. Also, verify that the text content of the captions adequately communicates all relevant information from the audio element, including speaker identification, dialogue transcripts, musical cues, and sound effects.

Below is an example code that demonstrates the addition of two tracks, one in English and another in Spanish.

<audio>
   <source src="conversation.mp3" type="audio/mp3">
   <track src="captions_en.vtt" kind="captions" srclang="en" label="english_captions">
   <track src="captions_es.vtt" kind="captions" srclang="es" label="spanish_captions">
</audio>

What this Accessibility Rule Checks

Checks the use of all HTML5 <audio> elements to ensure each contains a <track> element with the kind attribute value captions.

The list of 53 Input Purposes for User Interface Components are used as the basis for the programmatic definition of the purpose for each common input field that collects user data.

For screen readers to work properly, the autocomplete attribute values must be true and applied correctly.

Inaccessible content stems from missing autocomplete values in form fields. In the absence of the necessary autocomplete attribute values, screen readers will not read the identified autocomplete form fields.

When screen readers are unable to adequately notify users about the requirements for form field interaction, users cannot successfully navigate forms.

What this Accessibility Rule Checks

The purpose of each user-information-collecting input field can be established programmatically when:

• The input field fulfills a purpose specified in the Input Purposes for User Interface Components section, and
• The content is implemented using technologies that provide support for determining the desired meaning of form input data.

Ensure that the text spacing specified by style attributes is modifiable using custom stylesheets.

When lines of text are single-spaced, many people with cognitive difficulties have difficulty following them. Providing spacing between 1.5 and 2 makes it easier for them to begin a new line after finishing the previous one.

What this Accessibility Rule Checks

Text line spacing must be modifiable by custom stylesheets.