Parsing

Robust › 4.1 Compatible › WCAG 2.0

Overview

In content implemented using markup languages, elements have complete start and end tags, elements are nested according to their specifications, elements do not contain duplicate attributes, and any IDs are unique. Note: This criterion is considered obsolete and is no longer applicable in WCAG 2.2 due to improvements in modern browser parsing.

Note: This criterion is considered obsolete in WCAG 2.2. Modern browsers handle parsing robustly enough that this criterion is no longer practically applicable. It is retained in WCAG 2.2 documentation for backward compatibility, but conformance claims against WCAG 2.2 do not require evaluating this criterion.

Understanding

The W3C Web Accessibility Initiative (WAI) provides detailed guidance on understanding and implementing this criterion. The Understanding document covers the intent, benefits, and supporting techniques in depth.

Read Understanding 4.1.1 on W3C WAI

Techniques

W3C provides documented techniques for meeting this criterion. Each technique links to the full specification with code examples and test procedures.

How to Test

Run an HTML validator to check for parsing errors.
Test with multiple browsers and assistive technologies (NVDA, JAWS, VoiceOver).
Inspect ARIA roles and properties for correct usage.
Verify that status messages are programmatically exposed without receiving focus.

How VPATify tests this

VPATify runs automated WCAG checks against every page you scan and flags violations against individual success criteria. Our deep scan combines axe-core, contrast analysis, and structural checks to catch criterion-level failures that single-tool scans miss. See the full testing methodology and features for what's covered at each level.

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