On Input:
Understanding SC 3.2.2
3.2.2 On Input: Changing the setting of any user interface component does not automatically cause a change of context unless the user has been advised of the behavior before using the component. (Level A)
Intent of this Success Criterion
The intent of this Success Criterion is to ensure that entering data or selecting from a control has predictable effects. Changes in context can confuse users who do not easily perceive the change or are easily distracted by changes. Changes of context are appropriate only when it is clear that such a change will happen when a field is selected or a button is pressed.
Specific Benefits of Success Criterion 3.2.2:
This Success Criterion helps users with disabilities by making interactive content more predictable. Unexpected changes of context can be so disorienting for users with visual disabilities or cognitive limitations that they are unable to use the content.
Individuals who are unable to detect changes of context are less likely to become disoriented while navigating a site. For example:
Individuals who are blind or have low vision may have difficulty knowing when a visual context change has occurred, such as a new window popping up. In this case, warning users of context changes in advance minimizes confusion when the user discovers that the back button no longer behaves as expected.
Some individuals with low vision, with reading and intellectual disabilities, and others who have difficulty interpreting visual cues may benefit from additional cues in order to detect changes of context.
Examples of Success Criterion 3.2.2
A form is provided for creating calendar entries in a Web based calendaring and scheduling application. Along with the standard fields for subject, time and location, there is a set of radio buttons to select the type of calendar entry to create. The calendar entry type can be meeting, appointment or reminder. If the user selects the radio for meeting, additional fields are displayed on the page for entering the meeting participants. Different fields appear if the reminder button is chosen. Because only parts of the entry change and the overall structure remains the same the basic context remains for the user. Instructions at the beginning of the Web page explain the behavior of each radio button and the fields that appear when the button is selected.
A tab panel user interface is implemented within a Web page. The tab panel consists of 5 tabs, each with a different title and content: US News, World News, Weather, Entertainment, and Humor. As the user navigates from tab to tab using the arrow keys, the contents of the Web page are updated to reflect the selected tab. For example, when the user navigates to the Humor tab, A short account of a humorous incident is made visible in the tab panel, replacing the previous contents of the panel. This is the expected behavior of a tab panel user interface. The tab key can be used to navigate within the elements of the tab panel and then to other elements on the page below the current panel.
A form contains fields representing US phone numbers. All of the numbers have a three digit area code followed by a three digit prefix and finally a four digit number, and each part of the phone number is entered into a separate field. When the user completes the entry of one field and enter the first digit of the next field, the focus automatically moves to the next field of the phone number. This behavior of phone fields is described for the user at the beginning of the form.
Techniques and Failures for Success Criterion 3.2.2 - On Input
Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this Success Criterion. The techniques listed only satisfy the Success Criterion if all of the WCAG 2.0 conformance requirements have been met.
Sufficient Techniques
G80: Providing a submit button to initiate a change of context using a technology-specific technique listed below
G13: Describing what will happen before a change to a form control is made
H84: Using a button with a select element to perform an action (HTML)
Hiding and showing content based on a select element change (future link)
Hiding and showing content based on a radio element change (future link)
Additional Techniques (Advisory) for 3.2.2
Although not required for conformance, the following additional techniques should be considered in order to make content more accessible. Not all techniques can be used or would be effective in all situations.
Giving users advanced warning when opening a new window. (future link)
Common Failures for SC 3.2.2
The following are common mistakes that are considered failures of Success Criterion 3.2.2 by the WCAG Working Group.
Key Terms
- changes of context
major changes in the content of the Web page that, if made without user awareness, can disorient users who are not able to view the entire page simultaneously
Changes in context include changes of:
focus;
Note: A change of content is not always a change of context. Changes in content, such as an expanding outline or dynamic menu, do not necessarily change the context, unless they also change one of the above (e.g. focus).
Example 1: Opening a new window, moving focus to a different component, going to a new page (including anything that would look to a user as if they had moved to a new page) or significantly re-arranging the content of a page are examples of changes of context.
- user interface component
a part of the content that is perceived by users as a single control for a distinct function
Note 1: Multiple user interface components may be implemented as a single programmatic element. Components here is not tied to programming techniques, but rather to what the user perceives as separate controls.
Note 2: User interface components include form elements and links as well as components generated by scripts.
Example: An applet has a "control" that can be used to move through content by line or page or random access. Since each of these would need to have a name and be setable independently, they would each be a "user interface component."