a11y teacher edition W3C WCAG 2.2 & WCAG 3.0 draft reference
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Translating W3C Standards for Designers, Developers, QA & Product teams

SC 3.3.6 Level AAA Understandable

Error Prevention (All)

WCAG 2.2 success criterion • Guideline: Input Assistance

Tier 1 ยท The normative floor

Baseline compliance

What the normative text of WCAG 2.2 requires, and nothing more. Only a failure of this tier is a WCAG failure.

The bare minimum

For pages that require the user to submit information, at least one is true: submissions are reversible; input is checked and the user can correct it; or the user can review, confirm and correct before final submission.

Normative text

Verbatim from WCAG 2.2, W3C Recommendation 12 December 2024. Underlined terms are defined below.

For web pages that require the user to submit information, at least one of the following is true:

Reversible
Submissions are reversible.
Checked
Data entered by the user is checked for input errors and the user is provided an opportunity to correct them.
Confirmed
A mechanism is available for reviewing, confirming, and correcting information before finalizing the submission.

Definitions used (3)

Glossary definitions are normative. Their notes are informative.

web page

a non-embedded resource obtained from a single URI using HTTP plus any other resources that are used in the rendering or intended to be rendered together with it by a user agent

Informative notes (2)

Although any "other resources" would be rendered together with the primary resource, they would not necessarily be rendered simultaneously with each other.

For the purposes of conformance with these guidelines, a resource must be "non-embedded" within the scope of conformance to be considered a web page.

input error

information provided by the user that is not accepted

Informative notes (1)

This includes:

  1. Information that is required by the web page but omitted by the user
  2. Information that is provided by the user but that falls outside the required data format or values

mechanism

process or technique for achieving a result

Informative notes (2)

The mechanism may be explicitly provided in the content, or may be relied upon to be provided by either the platform or by user agents, including assistive technologies.

The mechanism needs to meet all success criteria for the conformance level claimed.

Tier 2 ยท The gap

Usability & user impact

Where content can meet this criterion and still make things harder for people with disabilities. These are not failures of SC 3.3.6, so raise them as usability defects. Known failures, including failures of related criteria, are listed in Tier 1.

None beyond 3.3.4. This extends it to every submission.

Tier 3 ยท The golden path

Recommended best practice

The pattern that meets the floor, closes the gap, and avoids audit disputes. A recommendation, not a requirement.

Validate inline and provide undo wherever it is practical.

W3C's Understanding document and techniques for SC 3.3.6 โ†— are informative: sufficient techniques show ways to pass, and documented failures show common ways to fail, but neither changes what the criterion requires.

How SC 3.3.6 maps to the WCAG 3 draft

From this site's reviewed map to the WCAG 3 editor's draft. It's an interpretation: W3C has not published a mapping.

Successor provisions

From WCAG 2.2, section 5.1: โ€œThe main content of WCAG 2.2 is normative and defines requirements that impact conformance claims. Introductory material, appendices, sections marked as "non-normative", diagrams, examples, and notes are informative (non-normative). Non-normative material provides advisory information to help interpret the guidelines but does not create requirements that impact a conformance claim.โ€