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Audit html-lang-valid

Ensure the lang attribute of the <html> element has a valid value

Impact:

Serious

WCAG-Konformität:

A
WCAG 3.1.1

Issue type:

failure

HTML page lang attribute has valid language tag

This rule checks that the `lang` attribute of the root element of a non-embedded HTML page has a language tag with a known primary language subtag.

Applicability

This rule applies to any document element if it is an html element for which all the following are true:

has a lang attribute that is neither empty ("") nor only ASCII whitespace; and
is in a top-level browsing context; and
has a node document with a content type of text/html.

Expectation

For each test target, the lang attribute has a known primary language tag.

Background

Assumptions

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.
This rule assumes that user agents and assistive technologies can programmatically determine known primary language tags even if these do not conform to the RFC 5646 syntax.
This rule assumes that only known primary language tags are enough to satisfy Success Criterion 3.1.1 Language of Page; this notably excludes grandfathered tags and ISO 639.2 three-letters codes, both having poor support in assistive technologies.

Accessibility Support

There are no accessibility support issues known.

This rule is only applicable to non-embedded HTML pages. HTML pages embedded into other documents, such as through iframe or object elements are not applicable because they are not web pages according to the definition in WCAG.

Related rules

Bibliography

Test Cases

Passed

Passed Example 1

This html element has a lang attribute with a known primary language tag.

<html lang="FR"></html>

Passed Example 2

This html element has a lang attribute with a known primary language tag even though the region subtag is not.

<html lang="en-US-GB"></html>

Failed

Failed Example 1

This html element has a lang attribute, with no known primary language tag.

<html lang="em-US"></html>

Failed Example 2

This html element has a lang attribute, with no known primary language tag.

<html lang="#1"></html>

Failed Example 3

The lang attribute of this page is an iso 639.2 three-letter code, which has no known primary language tag.

<html lang="eng">
	<body>
		<p lang="en">I love ACT rules!</p>
	</body>
</html>

Failed Example 4

The lang attribute of this page is a grandfathered tag, which has no known primary language tag.

<html lang="i-lux">
	<body>
		<p lang="lb">Lëtzebuerg ass e Land an Europa.</p>
	</body>
</html>

Inapplicable

Inapplicable Example 1

This rule does not apply to svg elements.

<svg xmlns="http://www.w3.org/2000/svg" lang="fr"></svg>

Autoren: Jey Nandakumar

Vorherige Autoren: Annika Nietzio

Finanzierung: WAI-Tools