Test Rule: Image button has accessible name

Description

This rule checks that each image button element has a accessible name.

Applicability

The rule applies to any HTML input element with a type attribute in the Image Button state, that is included in the accessibility tree.

Note: The specification of the type attribute describes in detail how to map the value of the attribute to its corresponding state.

Expectation

Each target element has an accessible name that is not empty ("").

Note: Testing that the accessible name is descriptive is not part of this rule and must be tested separately.

Assumptions

This rule assumes that all image buttons are user interface components as defined by WCAG 2.

Accessibility Support

There is a known combination of a popular browser and assistive technology that does not by default support title as an accessible name.

Background

Test Cases

Passed

Passed Example 1

The image button has an accessible name through the alt attribute.

<input type="image" src="/test-assets/shared/search-icon.svg" alt="Search" />

Passed Example 2

The image button has an accessible name through the aria-label attribute.

<input type="image" src="/test-assets/shared/search-icon.svg" aria-label="Search" />

Passed Example 3

The image button has an accessible name through the title attribute.

note: The title attribute may not always be accessibility supported.

<input type="image" src="/test-assets/shared/search-icon.svg" title="Search" />

Passed Example 4

The image button has an accessible name through the aria-labelledby attribute.

<input type="image" src="/test-assets/shared/search-icon.svg" aria-labelledby="id1" />
<div id="id1">Search</div>

Failed

Failed Example 1

The image button element has an empty accessible name. The name attribute can not be used to provide an accessible name.

<input type="image" name="search" src="/test-assets/shared/search-icon.svg" />

Failed Example 2

The image button has an empty alt attribute, and no other attributes that can give it an accessible name.

<input type="image" src="/test-assets/shared/search-icon.svg" alt="" />

Failed Example 3

The image button has an aria-labelledby attribute, but the referenced element does not exist. This gives the button an empty accessible name.

<input type="image" src="/test-assets/shared/search-icon.svg" aria-labelledby="non-existing" />

Inapplicable

Inapplicable Example 1

The button element is not an image button. Success Criterion 1.1.1 Non-text Content can not fail text buttons. Only non-text content is applicable.

<button>My button</button>

Inapplicable Example 2

The input element with type with a type attribute in the Button state is not an image button. Success Criterion 1.1.1 Non-text Content can not fail text buttons. Only non-text content is applicable.

<input type="button" value="My button" />

Inapplicable Example 3

The button element is tested separately from the img element. Success Criterion 4.1.2 Name, Role, Value is applied to the button, whereas the image is tested under Success Criterion 1.1.1 Non-text Content

<button><img src="/test-assets/shared/search-icon.svg" alt="Search" /></button>

Inapplicable Example 4

The img element is not a user interface component, and so is not tested for Success Criterion 4.1.2 Name, Role, Value.

<img src="/test-assets/shared/w3c-logo.png" alt="W3C logo" />

Inapplicable Example 5

The image button is ignored by assistive technologies because it is not included in the accessibility tree. These are not required to have an accessible name. If at some future state of the page the element gets included in the accessibility tree, an accessible name will be necessary.

<input type="image" src="/test-assets/shared/search-icon.svg" style="display: none;" />

Glossary

Accessible Name

The accessible name is the programmatically determined name of a user interface element that is included in the accessibility tree.

The accessible name is calculated using the accessible name and description computation.

For native markup languages, such as HTML and SVG, additional information on how to calculate the accessible name can be found in HTML Accessibility API Mappings 1.0, Accessible Name and Description Computation (working draft) and SVG Accessibility API Mappings, Name and Description (working draft).

For more details, see examples of accessible name.

Note: As per the accessible name and description computation, each element always has an accessible name. When no accessible name is provided, the element will nonetheless be assigned an empty ("") one.

Note: As per the accessible name and description computation, accessible names are flat string trimmed of leading and trailing whitespace. Notably, it is not possible for a non-empty accessible name to be composed only of whitespace since these must be trimmed.

Focusable

Elements that can become the target of keyboard input as described in the HTML specification of focusable and can be focused.

Included in the accessibility tree

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 (working draft) and the SVG accessibility API mappings (working draft).

For more details, see [examples of included in the accessibility tree][].

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-hidden attribute with a value of true. Such an element could still be interacted using sequential keyboard navigation regardless of the assistive technologies used, even though the element would not be included in the accessibility tree. [examples of included in the accessibility tree]: https://act-rules.github.io/pages/examples/included-in-the-accessibility-tree/

Outcome

An outcome is a conclusion that comes from evaluating an ACT Rule on a test subject or one of its constituent test target. An outcome can be one of the three following types:

Inapplicable: No part of the test subject matches the applicability
Passed: A test target meets all expectations
Failed: A test target does not meet all expectations

Note: A rule has one passed or failed outcome for every test target. When there are no test targets the rule has one inapplicable outcome. This means that each test subject will have one or more outcomes.

Note: Implementations using the EARL10-Schema can express the outcome with the outcome property. In addition to passed, failed and inapplicable, EARL 1.0 also defined an incomplete outcome. While this cannot be the outcome of an ACT Rule when applied in its entirety, it often happens that rules are only partially evaluated. For example, when applicability was automated, but the expectations have to be evaluated manually. Such “interim” results can be expressed with the incomplete outcome.

Implementations

This section is not part of the official rule. It is populated dynamically and not accounted for in the change history or the last modified date.

Implementation	Consistency	Complete	Report
Axe-core	Consistent	Yes	View Report
QualWeb	Consistent	Yes	View Report
SortSite	Consistent	Yes	View Report

Changelog

This is the first version of this ACT rule.