Success Criterion 3.2.2: On Input

Understanding Success Criterion: 

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.

Accessibility Level: 
A
Intent of Success Criterion: 

The intent of this Success Criterion is to ensure that entering data or selecting a form control has predictable effects. Changing the setting of any user interface component is changing some aspect in the control that will persist when the user is no longer interacting with it. So checking a checkbox, entering text into a text field, or changing the selected option in a list control changes its setting, but activating a link or a button does not. 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 in response to the user's action.
Note: This Success Criterion covers changes in context due to changing the setting of a control. Clicking on links or tabs in a tab control is activating the control, not changing the setting of that control.
Note: What is meant by "component" and "user interface component" here is also sometimes called "user interface element".

Specific Benefits of Success Criterion: 
  • 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.