Proposed Iframe element has non-empty accessible name

Description

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

Applicability

This rule applies to iframe elements that are included in the accessibility tree and for which all of the following are true:

• the iframe does not have a negative tabindex attribute value; and
• the iframe does not have an [explicit semantic role][] of presentation or none.

Expectation

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

Assumptions

If an iframe is not perceived by the user as a single control, it does not qualify as a user interface component under WCAG 2. In such a scenario, failing this rule would not fail success criterion 4.1.2. Unless the iframe is both removed from the accessibility tree and removed from sequential focus navigation, they usually are considered to be user interface components.

Accessibility Support

• Browser and assistive technology support for iframe elements is currently inconsistent. Some examples of inconsistencies include (but are not limited to):
  • There is a known combination of a popular browser and assistive technology that ignores aria-label and only announces title attribute as an accessible name
  • Some assistive technologies ignore empty iframe elements, regardless of if they are focusable or if they have an accessible name.
  • Some browsers instantly redirect focus from iframe elements to the first focusable element inside that iframe. This redirect makes it appear as though the iframe never receives focus. This occurs even if the iframe has a non-negative tabindex attribute value.
  • Not all browsers redirect focus on iframe elements. This ensures that the contents of iframe elements can be scrolled and accessed by using the keyboard. This must not be circumvented by using a negative tabindex, as this will make the iframe completely inaccessible for keyboard navigation.

Background

The frame element is deprecated, this rule does not consider frame or frameset elements.

Due to inconsistencies in handling focus on iframe, this rule ignores iframe elements for which there is an attempt to hide them from assistive technologies. Whether iframe elements that are inapplicable to this rule still require an accessible name varies between browsers.

Bibliography

• H64: Using the title attribute of the frame and iframe elements
• Understanding Success Criterion 4.1.2
• User interface component

Accessibility Requirements Mapping

• 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

Input Aspects

The following aspects are required in using this rule.

• DOM Tree
• CSS Styling

Test Cases

Passed

Passed Example 1

Open in a new tab

This iframe element gets its accessible name from the title attribute.

<iframe title="Grocery List" src="/test-assets/SC4-1-2-frame-doc.html"> </iframe>

Passed Example 2

Open in a new tab

This iframe element gets its accessible name from the aria-label attribute.

<iframe aria-label="Grocery list" src="/test-assets/SC4-1-2-frame-doc.html"> </iframe>

Passed Example 3

Open in a new tab

This iframe element gets its accessible name from the content of the div referenced with the aria-labelledby attribute.

<div id="frame-title-helper">Grocery List</div>
<iframe aria-labelledby="frame-title-helper" src="/test-assets/SC4-1-2-frame-doc.html"> </iframe>

Failed

Failed Example 1

Open in a new tab

This iframe element has an empty ("") accessible name. The name attribute is not used in computing the accessible name of iframe elements.

<iframe name="Grocery List" src="/test-assets/SC4-1-2-frame-doc.html"> </iframe>

Failed Example 2

Open in a new tab

This iframe element has no attributes that would give it a non-empty ("") accessible name.

<iframe src="/test-assets/SC4-1-2-frame-doc.html"> </iframe>

Failed Example 3

Open in a new tab

This iframe element has an empty ("") accessible name because the title attribute has an empty string as its value.

<iframe title="" src="/test-assets/SC4-1-2-frame-doc.html"> </iframe>

Failed Example 4

Open in a new tab

This iframe element has an empty ("") accessible name because the title attribute value is trimmed of whitespace by the accessible name computation.

<iframe title=" " src="/test-assets/SC4-1-2-frame-doc.html"> </iframe>

Inapplicable

Inapplicable Example 1

Open in a new tab

This page has no iframe element.

<button>take me somewhere</button>

Inapplicable Example 2

Open in a new tab

This iframe is not included in the accessibility tree because of setting a style of display: none;.

<iframe style="display:none;" src="/test-assets/SC4-1-2-frame-doc.html"></iframe>

Inapplicable Example 3

Open in a new tab

This iframe element has a negative tabindex attribute value.

<iframe tabindex="-1" src="/test-assets/SC4-1-2-frame-doc.html" style="height: 250px"> </iframe>

Inapplicable Example 4

Open in a new tab

This iframe element has an [explicit semantic role][] of none.

<iframe src="/test-assets/SC4-1-2-frame-doc.html" role="none"> </iframe>

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.

Attribute value

The attribute value of a content attribute set on an HTML element is the value that the attribute gets after being parsed and computed according to specifications. It may differ from the value that is actually written in the HTML code due to trimming whitespace or non-digits characters, default values, or case-insensitivity.

Some notable case of attribute value, among others:

• For enumerated attributes, the attribute value is either the state of the attribute, or the keyword that maps to it; even for the default states. Thus <input type="image" /> has an attribute value of either Image Button (the state) or image (the keyword mapping to it), both formulations having the same meaning; similarly, “an input element with a type attribute value of Text” can be either <input type="text" />, <input /> (missing value default), or <input type="invalid" /> (invalid value default).
• For boolean attributes, the attribute value is true when the attribute is present and false otherwise. Thus <button disabled>, <button disabled="disabled"> and <button disabled=""> all have a disabled attribute value of true.
• For attributes whose value is used in a case-insensitive context, the attribute value is the lowercase version of the value written in the HTML code.
• For attributes that accept numbers, the attribute value is the result of parsing the value written in the HTML code according to the rules for parsing this kind of number.
• For attributes that accept sets of tokens, whether space separated or comma separated, the attribute value is the set of tokens obtained after parsing the set and, depending on the case, converting its items to lowercase (if the set is used in a case-insensitive context).
• For aria-* attributes, the attribute value is computed as indicated in the WAI-ARIA specification and the HTML Accessibility API Mappings.

This list is not exhaustive, and only serves as an illustration for some of the most common cases.

The attribute value of an IDL attribute is the value returned on getting it. Note that when an IDL attribute reflects a content attribute, they have the same attribute value.

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.

Whitespace

Whitespace are characters that have the Unicode “White_Space” property in the Unicode properties list.

This includes:

• all characters in the Unicode Separator categories, and

• the following characters in the Other, Control category:

  • Character tabulation (U+0009)
  • Line Feed (LF) (U+000A)
  • Line Tabulation (U+000B)
  • Form Feed (FF) (U+000C)
  • Carriage Return (CR) (U+000D)
  • Next Line (NEL) (U+0085)

Rule Versions

This is the first version of this ACT rule.

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 4.6.0	Automated tool	Consistent
QualWeb 3.0.0	Automated tool	Consistent
SortSite 6.45	Automated tool	Partial
Total Validator 17.1.0	Linter	Consistent
Total Validator (+Browser) 17.1.0	Automated tool	Consistent