Level AAWCAG 2.0

3.3.4 Error Prevention (Legal, Financial, Data)

For pages that cause legal commitments or financial transactions, that modify or delete user-controllable data, or that submit test responses, submissions are reversible, checked for errors, or confirmed before finalizing.

Last reviewed: September 9, 2026

Understanding 3.3.4

This criterion adds safeguards to high-stakes transactions (legal agreements, purchases, deleting data, or test submissions) where a mistake can be costly or irreversible. It protects everyone, but especially people with cognitive or motor disabilities who may be more prone to an accidental submission, by requiring a way to catch mistakes before they become permanent.

How to Meet It

For qualifying pages, do at least one of the following: make the action reversible (for example, allow order cancellation within a window, or provide undo for deletions); provide a review step where the user can check and correct all data before final submission; or require explicit confirmation, such as a confirmation dialog, before the action is finalized.

Code Examples

INCORRECT

<button onclick="deleteAccount()">Delete Account</button>
<!-- Immediately and irreversibly deletes data on a single click -->

CORRECT

<button onclick="showConfirmDialog()">Delete Account</button>
<div role="alertdialog" aria-labelledby="confirm-title">
  <h2 id="confirm-title">Confirm account deletion</h2>
  <p>This action is permanent and cannot be undone. Are you sure?</p>
  <button onclick="deleteAccount()">Yes, delete my account</button>
  <button onclick="closeDialog()">Cancel</button>
</div>

Frequently Asked Questions

Does an e-commerce checkout need a review-order page?

A review step showing items, shipping details, and total cost, with a chance to edit before paying, is the most common way to satisfy this criterion for financial transactions. A cancellation window or an explicit confirmation step can also satisfy it, but a review step is generally the most user-friendly option.

Related Success Criteria

3.3.1 Error Identification 3.3.2 Labels or Instructions 3.3.3 Error Suggestion 3.3.5 Help

Quick Facts

Criterion3.3.4
LevelAA
IntroducedWCAG 2.0

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