If an input error is automatically detected and suggestions for correction are known, then the suggestions are provided to the user, unless it would jeopardize the security or purpose of the content. (Level AA)

Rationale

This checkpoint ensures that the application offers users suggestions to correct input errors. People with visual impairment or cognitive disabilities can correct input errors more easily if the application suggests a correct value or enables users to select a correct value from a list. The ability to select a suggested or correct value from a list requires less movement of the hands and fingers for people with physical disabilities.

Refer to Understanding SC 3.3.3 for more information (external link to WCAG).

Development Techniques

Review the General techniques as well as other tabs applicable to your technology.  Prioritize the use of technology-specific techniques, and implement the General techniques as needed. You are always required to find, understand and implement accessible code techniques to meet the checkpoint. The documented techniques and supplements are not exhaustive; they illustrate acceptable ways to achieve the spirit of the checkpoint. If numbered, techniques are in order of preference, with recommended techniques listed first. Where used, IBM information that complements the WCAG techniques is indicated as supplemental.

General techniques

Instructions: Select the situation below that matches your content. Items in the described situation are sufficient techniques for applicable cirucmstances.

Situation A: If a mandatory field contains no information

Situation B: If information for a field is required to be in a specific data format

Situation C: Information provided by the user is required to be one of a limited set of values

Web (HTML, ARIA, CSS) techniques

Instructions: In addition to the General techniques, any of these Web techniques are deemed sufficient in the following situations when used as instructed.

Situation A: If a mandatory field contains no information:

Situation B: If information for a field is required to be in a specific data format

Situation C: Information provided by the user is required to be one of a limited set of values:

All techniques in Situation B apply to Situation C as well.

Web supplements

The following techniques, examples and comments provide additional information beyond that available in the WCAG techniques.

Using an ARIA alert role to provide error suggestions

In the third bullet in the WCAG G83 examples, a user completing a form tabs away from a required field without entering a value. A client-side validation script detects that the field is empty and displays a message to notify the user that the field is required. To ensure such a message is detectable by screen readers, assign a WAI-ARIA role="alert".

The same technique can be used to describe the nature of an error when a value must be in a specific data format or range, in order to meet G85: Providing a text description when user input falls outside the required format or values and G84: Providing a text description when the user provides information that is not in the list of allowed values. Assigning the message a role of alert ensures its successful detection by screen readers.

Mobile Native (iOS) techniques

There are no specific Mobile Native iOS techniques for this checkpoint. Refer to the General techniques section.

Eclipse techniques

Instructions: In addition to the General techniques, the Eclipse techniques in this section represent a technique or combination of techniques deemed sufficient for meeting this checkpoint (3.3.3).

Provide descriptive text by using MessageBox or ErrorDialog

When a user enters invalid input, provide descriptive text identifying valid values through a MessageBox or ErrorDialog as outlined in Checkpoint 3.3.1 Error Identification Eclipse techniques.

Define relations between invalid field and descriptive text

When a user enters invalid input, provide descriptive text identifying valid values via  relations between the invalid field and descriptive text as outlined in Checkpoint 3.3.1 Error Identification Eclipse techniques.

Provide descriptive text when input is required

When a user fails to enter required input, provide descriptive text identifying the required field or fields as outlined in Checkpoint 3.3.1 Error Identification Eclipse techniques.

Windows-based (MSAA+IA2) techniques

Instructions: In addition to the General techniques, the Windows-based (MSAA+IA2) techniques in this section represent a technique or combination of techniques deemed sufficient for meeting this checkpoint (3.3.3).

Provide descriptive text by using MessageBox

When a user enters invalid input, provide descriptive text identifying valid values through a MessageBox as outlined in Checkpoint 3.3.1 Error Identification Windows-based techniques.

Define relations between invalid field and descriptive text

When a user enters invalid input, provide descriptive text identifying valid values via relations between the invalid field and descriptive text as outlined in Checkpoint 3.3.1 Error Identification Windows-based techniques.

Provide descriptive text when input is required

When a user fails to enter required input, provide descriptive text identifying the required field or fields as outlined in Checkpoint 3.3.1 Error Identification Windows-based techniques.


Most links in this checklist reside outside ibm.com at the Web Content Accessibility Guidelines (WCAG) 2.0. W3C Recommendation 11 December 2008: http://www.w3.org/TR/WCAG20/

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