4.1.1 Parsing (Obsolete)

What this criterion requires

Note: this criterion was removed in WCAG 2.2 and is treated as always satisfied in current WCAG 2.1 conformance reporting. It is kept here because older audit reports and tooling still reference it.

Historic criterion requiring well-formed markup: complete tags, properly nested elements, no duplicate attributes, unique IDs. It was removed in WCAG 2.2 and is now treated as always satisfied in WCAG 2.1 conformance reporting, because modern browsers and assistive technologies parse imperfect HTML consistently.

Who it helps

Originally, users of assistive technologies that parsed markup directly. Modern browser engines have made the concern obsolete.

Example: fails vs passes

<div id="menu">...</div>
    <div id="menu">...</div>  <!-- duplicate IDs -->

<div id="menu-main">...</div>
    <div id="menu-footer">...</div>

The criterion itself is retired (removed in WCAG 2.2), but duplicate IDs still break label and ARIA references - fix them under 1.3.1/4.1.2.

How to meet and fix it

• Nothing is required for new conformance claims - WCAG 2.2 removed the criterion and W3C guidance treats it as met in 2.1
• Still fix duplicate IDs and broken nesting when found: they cause real bugs under 1.3.1 and 4.1.2

Common failures auditors find

• Legacy audit reports still listing 4.1.1 findings - re-map real issues to 1.3.1 or 4.1.2

Automated scanning catches a share of these instantly - run a free check - and a manual audit covers the judgement calls a tool cannot make.

Last updated 12 August 2026. Reviewed by the EqualWeb accessibility team.