Techniques for WCAG 2.0

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G83: Providing text descriptions to identify required fields that were not completed


Content that includes mandatory fields in user input

This technique relates to:


The objective of this technique is to notify the user when a field that must be completed has not been completed. When users fail to provide input for any mandatory form fields, information is provided in text to enable the users to identify which fields were omitted. One approach is to use client-side validation and provide an alert dialog box identifying the mandatory fields which were omitted. Another approach, using server-side validation, is to re-display the form (including any previously entered data), with either a text description at the location of the omitted mandatory field, or a text description that identifies the omitted mandatory fields.

Note: The best practice is to include a message or alert, as some users may not be aware that an error has occurred and could assume that the form is not functioning correctly. It is also best practice to include an error notification in the page title (title element) since a screen reader user is likely to believe the page was submitted correctly and continue to navigate to another page as soon as the new page is returned instead of reading the main content area of the page again.




  1. Fill out a form, deliberately leaving one or more required (mandatory) fields blank, and submit it.

  2. Check that a text description is provided identifying the mandatory field(s) that was not completed.

  3. Check that other data previously entered by the user is re-displayed, unless the data is in a security related field where it would be inappropriate to retain the data for re-display (e.g. password).

Expected Results

If this is a sufficient technique for a success criterion, failing this test procedure does not necessarily mean that the success criterion has not been satisfied in some other way, only that this technique has not been successfully implemented and can not be used to claim conformance.

Techniques are Informative

Techniques are informative—that means they are not required. The basis for determining conformance to WCAG 2.0 is the success criteria from the WCAG 2.0 standard—not the techniques. For important information about techniques, please see the Understanding Techniques for WCAG Success Criteria section of Understanding WCAG 2.0.