HTML page has lang attribute
This rule checks that an HTML page has a non-empty
This rule applies to any document element if it is an
html element for which all the following are true:
- is in a top-level browsing context; and
- has a node document with a content type of
html elements within
object elements are not applicable as
object elements create nested browsing contexts. However, as these elements are meant to provide a layer of isolation, the declared language of their parent browsing context will likely not be inherited, making it possible for empty
lang attributes in nested browsing contexts to also cause accessibility issues.
Each test target has a
lang attribute value that is neither empty (
"") nor only ASCII whitespace.
The language of the page can be set by other methods than the
lang attribute, for example using HTTP headers or the
meta element. These methods are not supported by all assistive technologies. This rule assumes that these other methods are insufficient to satisfying Success Criterion 3.1.1: Language of Page.
There are no major accessibility support issues known for this rule.
- Understanding Success Criterion 3.1.1: Language of Page
- H57: Using language attributes on the html element
- RFC 5646: Tags for Identifying Languages
Accessibility Requirements Mapping
3.1.1 Language of Page (Level A)
- Learn more about 3.1.1 Language of Page
- Required for conformance to WCAG 2.0 and later on level A and higher.
- Outcome mapping:
failedoutcomes: success criterion is not satisfied
passedoutcomes: success criterion needs further testing
inapplicableoutcome: success criterion needs further testing
H57: Using language attributes on the html element
- Learn more about technique H57
- Not required for conformance to any W3C accessibility recommendation.
- Outcome mapping:
failedoutcomes: technique is not satisfied
passedoutcomes: technique needs further testing
inapplicableoutcome: technique needs further testing
The following aspects are required in using this rule.
Passed Example 1
html element has a
lang attribute with a non-empty (
Failed Example 1
html element does not have a
Failed Example 2
html element has a
lang attribute with an empty (
Failed Example 3
html element has a
lang attribute whose value is only ASCII whitespace.
<html lang=" "></html>
Failed Example 4
html element has no
lang attribute, only a
Inapplicable Example 1
This rule does not apply to an
Inapplicable Example 2
This rule does not apply to a
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
typeattribute 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
truewhen the attribute is present and
<button disabled="">all have a
disabledattribute value of
- 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).
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.
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
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
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
- Proposed version, 21 June 2022 (compare)
- Latest version, 28 January 2022
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.