Clausecheck

All checks / html-has-lang

<html> element must have a lang attribute

Ensure every HTML document has a lang attribute

Check IDhtml-has-lang
EN 301 5499.3.1.1
WCAG 2.1 SC3.1.1
LevelA

Why this is a legal issue in the EU

The European Accessibility Act requires covered digital services to meet the harmonised standard EN 301 549. Clause 9 of that standard adopts the WCAG 2.1 Level AA success criteria directly, so a failure of SC 3.1.1 is a failure of EN 9.3.1.1 — which is the reference a supervising authority or a complainant will cite, not the WCAG number on its own.

What an automated check can and cannot tell you

The html-has-lang check is machine-decidable: where it reports a failure, the failure is real. It cannot confirm the opposite. Passing this check does not mean you satisfy EN 9.3.1.1, because parts of that criterion depend on human judgement about meaning and context.

Related clauses

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Reference

Full technique documentation for html-has-lang →