Image button has non-empty accessible name

Description

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

Applicability

This rule applies to any input element with a type attribute value of image, and that is included in the accessibility tree.

Expectation

Each target element has an accessible name that is neither empty (""), nor the default name for this element (localized version of “Submit Query”).

Assumptions

• This rule assumes that all image buttons are user interface components as defined by WCAG 2.
• This rule assumes that the default name for image buttons (“Submit Query”), as defined by the HTML Accessibility API Mapping, is never descriptive.

Accessibility Support

The input type=”image” Accessible Name Computation algorithm uses the first non-empty name, but some user agents and assistive technologies combinations stop at the first existing one, even if empty.

Background

Contrarily to img elements, an empty alt attribute (alt="") does not make an image button decorative; image buttons have a button role and are therefore exposed as interactive elements. Consequently, an empty alt attribute does not provide a “usable string” for image buttons and the computation defaults to other means of providing a name, as defined in input type=”image” Accessible Name Computation algorithm.

Related rules

• Button has non-empty accessible name

Bibliography

• Understanding Success Criterion 1.1.1: Non-text Content
• Understanding Success Criterion 4.1.2: Name, Role, Value
• WCAG Technique H36: Using alt attributes on images used as submit buttons
• HTML Accessibility API Mappings for computing the accessible name of image buttons

Accessibility Requirements Mapping

• 1.1.1 Non-text Content (Level A)

  • Learn more about 1.1.1 Non-text Content
  • Required for conformance to WCAG 2.0 and later on level A and higher.
  • Outcome mapping:
    • Any failed outcomes: success criterion is not satisfied
    • All passed outcomes: success criterion needs further testing
    • An inapplicable outcome: success criterion needs further testing
• 4.1.2 Name, Role, Value (Level A)

  • Learn more about 4.1.2 Name, Role, Value
  • Required for conformance to WCAG 2.0 and later on level A and higher.
  • Outcome mapping:
    • Any failed outcomes: success criterion is not satisfied
    • All passed outcomes: success criterion needs further testing
    • An inapplicable outcome: success criterion needs further testing
• G94: Providing short text alternative for non-text content that serves the same purpose and presents the same information as the non-text content

  • Learn more about technique G94
  • Not required for conformance to any W3C accessibility recommendation.
  • Outcome mapping:
    • Any failed outcomes: technique is not satisfied
    • All passed outcomes: technique needs further testing
    • An inapplicable outcome: technique needs further testing
• G95: Providing short text alternatives that provide a brief description of the non-text content

  • Learn more about technique G95
  • Not required for conformance to any W3C accessibility recommendation.
  • Outcome mapping:
    • Any failed outcomes: technique is not satisfied
    • All passed outcomes: technique needs further testing
    • An inapplicable outcome: technique needs further testing

Input Aspects

The following aspects are required in using this rule.

• DOM Tree
• CSS Styling

Test Cases

Passed

Passed Example 1

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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

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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

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

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

Passed Example 4

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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

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The image button element has an accessible name equal to the default “Submit Query”. 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

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The image button has an empty alt attribute, and no other attributes that can give it an accessible name, hence its name is the default “Submit Query”.

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

Failed Example 3

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The image button has an aria-labelledby attribute, but the referenced element does not exist. This gives the button the default accessible name of “Submit Query”.

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

Inapplicable

Inapplicable Example 1

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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

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The input element with the type attribute value of button 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

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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

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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

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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

An element is focusable if one or both of the following are true:

• the element is part of sequential focus navigation; or
• the element has a tabindex value that is not null.

Exception: Elements that lose focus during a period of up to 1 second after gaining focus, without the user interacting with the page the element is on, are not considered focusable.

Notes:

• The 1 second time span is an arbitrary limit which is not included in WCAG. Given that scripts can manage the focus state of elements, testing the focusability of an element consistently would be impractical without a time limit.
• The tabindex value of an element is the value of the tabindex attribute parsed using the rules for parsing integers. For the tabindex value to be different from null, it needs to be parsed without errors.

Included in the accessibility tree

Elements included in the accessibility tree of platform specific accessibility APIs are exposed to assistive technologies. This allows users of assistive technology to access the elements in a way that meets 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.

Programmatically hidden elements are removed from the accessibility tree. However, some browsers will leave focusable elements with an aria-hidden attribute set to true in the accessibility tree. Because they are hidden, these elements are considered not included in the accessibility tree. This may cause confusion for users of assistive technologies because they may still be able to interact with these focusable elements using sequential keyboard navigation, even though the element should not be 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.

Programmatically Hidden

An HTML element is programmatically hidden if either it has a computed CSS property visibility whose value is not visible; or at least one of the following is true for any of its inclusive ancestors in the flat tree:

• has a computed CSS property display of none; or
• has an aria-hidden attribute set to true

Note: Contrary to the other conditions, the visibility CSS property may be reverted by descendants.

Note: The HTML standard suggests setting the CSS display property to none for elements with the hidden attribute. While not required by HTML, all modern browsers follow this suggestion. Because of this the hidden attribute is not used in this definition. In browsers that use this suggestion, overriding the CSS display property can reveal elements with the hidden attribute.

Rule Versions

1. Latest version, 31 August 2023 (compare)
   • Add clarification about empty attributes to Background and Accessibility support
2. Previous version, 23 June 2022 (compare)
   • Account for focus redirects in "focusable" definition
   • Let hidden attribute be handled by display:none in "programmatically hidden" definition
3. Previous version, 28 January 2022

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	Type	Consistency	Report
Alfa (fully automated) 0.57.2	Automated tool	Consistent
Alfa (semi-automated) 0.57.2	Semi-automated tool	Consistent
Axe DevTools Pro 4.37.1	Semi-automated tool	Consistent
Axe-core 4.8.1	Automated tool	Consistent
Equal Access Accessibility Checker 3.1.42-rc.0	Automated tool	Consistent
QualWeb 3.0.0	Automated tool	Consistent
SortSite 6.45	Automated tool	Consistent
Total Validator 17.1.0	Linter	Consistent
Total Validator (+Browser) 17.3.0	Automated tool	Consistent