Accessibility Checking for Large Sites

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.

To express their purpose and meaning to screen reader users, all images must include alternate text.

Even if the image just contains text, screen readers have no way of translating it into words that are read to the user. As a result, photos must have concise, descriptive alt text so that screen reader users grasp the image’s contents and purpose.

If you can’t see, all visual information, such as photographs, is meaningless unless a digital text equivalent is provided so that screen readers may translate that text into either sound or braille. People with limited eyesight or colorblindness experience the same phenomenon to varied degrees.

Screen readers cannot translate an image into speech or braille to make it available by sound or touch if you do not provide a suitable alternative that works for their available sensory modalities, such as making an image accessible by providing a digital text description.

What this Accessibility Rule Checks

Ensures that all <image> elements have alternative text and either role="presentation" or role="none" (ARIA 1.1).

Ensures that input buttons have legible text.

Without an accessible name, screen reader users cannot determine the purpose of a input type="button".

Without a discernible and accessible name, screen reader users cannot grasp the purpose of an image. A title for a photograph may just convey advisory information about the image. When used as a control, unnamed actionable visual images such as buttons have no clear definition of the destination, purpose, function, or action for the non-text material.

What this Accessibility Rule Checks

The text on input buttons must be readable.

Makes certain that <input type="image"> elements have alternate text.

Screen reader users will not understand the function of a <input type="image"> button unless equivalent wording is provided. Even if the image merely contains text, alternate text is required because a screen reader cannot interpret images of words into output.

Simply typing text adjacent to the form element will not result in a true label. Screen readers, for example, require labels in code that can be determined automatically.

Some screen readers are configured to estimate the label based on the surrounding text, however this method is not foolproof and might cause confusion if the screen reader guesses incorrectly.

What this Accessibility Rule Checks

Ensures that each <input type="image"> has a name that can be found.

Each form element must have a label element attached with it programmatically.

Forms must have effective form labels in order to be accessible. Form elements like as checkboxes, radio buttons, input fields, etc. are frequently self-explanatory to sighted users, even if they are not programmatically labeled. Users with screen readers require descriptive form labels to identify form fields. Adding labels to all form elements removes uncertainty and makes the product more accessible.

When form elements lack labels, screen reader users are unaware of the expected data input. Screen readers cannot determine information about input items programmatically in the absence of an established label association (or redundant text functioning as a label).

Since clicking the label activates the control, people with weak motor control do not benefit from a bigger clickable area for the control.

What this Accessibility Rule Checks

Ensures that each form element has a label associated with it programmatically.

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.

ARIA widget roles must contain attributes describing the widget’s state or properties.

ARIA widget roles necessitate additional properties describing the widget’s state. If a needed attribute is missing, the widget’s status is not conveyed to users of screen readers.

Some roles function as composite user interface widgets. As such, they serve as containers that manage the widgets they contain. When an object inherits from several ancestors and one ancestor indicates support for a property and another says the property is required, the property becomes required on the inheriting object. In some circumstances, default values are sufficient to meet ARIA attribute requirements.

When required state and property attributes for specific roles (and subclass roles) are missing, screen readers may be unable to communicate the element’s role definition to the user.

What this Accessibility Rule Checks

Checks all elements with the role attribute to ensure that all necessary attributes are defined.

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.

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.