WCAG 3.3.4 Prevent Serious Errors

Make suggestions on how to fix errors on forms.

For any web pages that have important implications (legal commitments, rights waivers, spending money, scheduling reservations, etc.), make sure that at least one of the following options is available:

  1. Submissions are reversible
  2. Input is checked for errors and the user is provided an opportunity to co correct errors
  3. There is an option to review, confirm, and correct information before finalizing the submission

What to do?

  • Provide ample opportunity for users to review and correct any potential errors, especially when it comes to stuff with big implications

Examples of Big Implications

  • Legal contracts
  • Money being spent
  • Reservations


Plain English Explanation

All 3.3.4 is getting at is we want to make sure everyone gets their desired result when making a submission, especially when it comes to things with big implications. 

For example, imagine the difference one “0” can make it when it comes to buying a $25 stock.  If instead of entering “100” shares to purchase, I enter “1000”, I just committed to spend $25,000 instead of $2,500. Or imagine, if when booking a hotel, I select “2021” as my year instead of “2020”.

As we all know, it’s extremely easy to make these types of errors.  And this is why it’s so crucial that we provide users with ample opportunity to review, correct, and/or reverse any submissions they make on our website.

I recommend you incorporate as many ways as possible to prevent errors:

  1. Where feasible, allow users to reverse a submission after it is made.  For example, you provide for a window of time for someone to completely cancel/undo/delete a submission or agreement.
  2. Always automatically check for detectable errors and provide an opportunity to correct them.
  3. Before any final submission is made, users are given an opportunity to review, confirm, and/or correct a potential submission.

If your website potentially falls under the serious implications/transactions category (think legal, financial, data, reservations, and anything else with big impact), scrutinize your form submission process heavily.