3.3.6 Error Prevention (All)
Level AAA · added in WCAG 2.0
Any page that asks users to submit information must offer at least one safeguard: the submission can be reversed, the input is checked and users can fix errors, or users can review and confirm first. This is a level AAA criterion: most laws and policies require AA, but it is still worth meeting where you can.
Who it helps
People with cognitive, motor or visual disabilities make input mistakes more often and may not notice them before submitting. A chance to check, confirm or undo helps them on every form, not only payment forms.
How to meet it
- Validate every form and let users correct errors before the data is accepted.
- Offer an undo for quick actions, such as sending a message, archiving an item or posting a comment.
- Add a review step to long or multi-step forms, such as applications and surveys.
- Ask for confirmation before actions that are hard to reverse, and name what will happen.
- Cover every form type, including contact, comment, settings and search forms, not only those 3.3.4 covers.
Examples
<form action="/comments" method="post">
<label for="c">Comment</label>
<textarea id="c" name="comment"></textarea>
<button type="submit">Post</button>
</form><div role="status">
Your comment was posted.
<a href="/comments/981/edit">Edit</a>
<form action="/comments/981/delete" method="post">
<button type="submit">Undo</button>
</form>
</div><form action="/comments/preview" method="post">
<label for="c">Comment</label>
<textarea id="c" name="comment" required></textarea>
<button type="submit">Preview comment</button>
</form>Can a scanner detect this?
No
axe-core has no rule for this criterion, because safeguards like undo and review exist only across steps of a process. A person must submit each form and check that it can be reversed, is checked for errors or asks for confirmation.
No automated rule tests this criterion. Check it by hand.
Common mistakes
- Protecting checkout but leaving settings changes and messages with no undo or confirmation.
- Offering an undo that disappears after a second or two, before users can reach it.
- Clearing the form after an error, so users must start again instead of correcting the mistake.
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