SIA-R7`lang` attributes within the `<body>` element have a valid value

Accessibility requirements

This rule tests conformance of the following accessibility requirements:

3.1.2 Language of Parts

Description

This rule checks that lang attributes specified on elements within the <body> element have a valid value.

Applicability

This rule applies to every element in the HTML namespace that:

is an inclusive descendant in the flat tree of a <body> element; and
has a lang attribute that is neither empty nor only ASCII whitespace; and
there is some non-whitespace only text inheriting its programmatic language from this element.

Expectations

The value of the attribute is a valid language tag.

Assumptions

This rule makes the following assumption:

The lang attribute is being used to conform to WCAG. As such, this rule doesn't test if the attribute is needed to conform to WCAG.

Accessibility support

This rule has no known accessibility support concerns.

Examples

Passed

These lang attributes are valid language tags and therefore pass the rule:

<article lang="en"></article>

<blockquote lang="fr-CH"></blockquote>

Failed

These lang attributes are not valid language tags and therefore fail the rule:

<p lang="english"></p>

<article lang="xyz"></article>

Inapplicable

This document has an element that has a lang attribute with a value that is a valid language tag, but the element is not within the <body> element and is therefore inapplicable:

<html lang="en">
    <body></body>
</html>

This element that has a lang attribute with a value that is empty and is therefore inapplicable:

<article lang=""></article>

This element that has a lang attribute with a value that is only ASCII whitespace and is therefore inapplicable:

<article lang=" "></article>

SIA-R7lang attributes within the <body> element have a valid value