3.3.4 Error Prevention (Legal, Financial, Data)
Level AA · added in WCAG 2.0
Pages that create legal commitments or financial transactions, change or delete user data, or submit test answers must let users avoid serious mistakes. At least one must be true: the submission can be reversed, the input is checked and users can fix errors, or users can review and confirm before it is final.
Who it helps
People with reading, motor or cognitive disabilities are more likely to make mistakes, such as a mistyped amount or a wrong date. Screen reader users may not notice an error before submitting. A review step or undo protects them from costly results.
How to meet it
- Add a review page before a payment or contract is final, showing all details with options to edit or confirm.
- Check input for errors, such as an invalid card number or a date in the past, and let users correct it before submitting.
- Make actions reversible where possible, such as cancelling an order within a stated time or restoring deleted items.
- Ask for confirmation before deleting data, such as a checkbox or a second step that names what will be deleted.
- Apply the same care to online tests: let users review answers before the final submit.
Examples
<form action="/pay" method="post">
<p>Transfer $1,250.00 to account 4417 0021</p>
<button type="submit">Pay</button>
</form><form action="/account/delete" method="post">
<button type="submit">Delete account</button>
</form><form action="/pay/confirm" method="post">
<h2>Review your transfer</h2>
<p>Amount: $1,250.00. To: account 4417 0021. Date: Nov 3, 2026.</p>
<a href="/pay/edit">Edit details</a>
<button type="submit">Confirm and pay $1,250.00</button>
</form><form action="/account/delete" method="post">
<p>This permanently deletes your account and 32 saved projects.</p>
<input type="checkbox" id="sure" name="confirm" required>
<label for="sure">I understand this cannot be undone</label>
<button type="submit">Delete account</button>
</form>Can a scanner detect this?
No
axe-core has no rule for this criterion, because it cannot tell which forms carry legal, financial or data risk. A person must walk through each such process and confirm it is reversible, checked or confirmed.
No automated rule tests this criterion. Check it by hand.
Common mistakes
- Using one-click purchase or transfer with no way to review or cancel.
- Showing a confirmation dialog that does not repeat the key details, such as the amount or what will be deleted.
- Deleting records immediately with no undo, recycle bin or confirmation step.
- Submitting a timed test as soon as the last question is answered, with no review.
Related criteria
Check your own page
See which automated WCAG checks your page fails, with the failing elements and how to fix them.
Reviewed November 2, 2026