WCAG 2.1 - SC 3.3.4 Error Prevention (Legal, Financial, Data)

If a web page creates legal commitments or financial transactions, or modifies or deletes stored user data, or submits user test responses, the user submission must be either reversible, the data must be checked for input errors and the user given a chance to correct any errors found, or the user must be given a chance to review their submission and must confirm that the information is correct before finalizing the submission.

Users with disabilities may be more likely to make mistakes. People with reading disabilities may transpose numbers and letters, and those with motor disabilities may hit keys by mistake. Providing the ability to reverse actions allows users to correct a mistake that could result in serious consequences. Providing the ability to review and correct information gives the user an opportunity to detect a mistake before taking an action that has serious consequences.

Official Requirements:

3.3.4 Error Prevention (Legal, Financial, Data): For Web pages that cause legal commitments or financial transactions for the user to occur, that modify or delete user-controllable data in data storage systems, or that submit user test responses, at least one of the following is true:

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

How to fix:

• If a page causes a legal transaction to occur, provide a stated period of time during which the transaction can be updated or canceled by the user
• Give the user a chance to review and correct information before finalizing the process.
• Provide a checkbox that the user has to check, indicating that they have read and verified all the information being submitted.
• If the user action results in information being deleted, provide a way to recover the deleted information.
• Ask for user confirmation before performing any irreversible actions.