3.2.2

3.2.2 On Input

WCAG says:

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.

When this is applicable

When there are interactive elements (form elements or other interactive objects that change something on the page, but no standard links or buttons).

Check interactive elements

Check twice, once with keyboard only and once with a mouse or trackpad.

Select and fill all interactive elements (except buttons and links).

Check that context does not change unexpectedly, in particular:

• that changes of content are not excessive and don't change the meaning of the page - changes of (bits of) content are fine if they happen underneath the triggering element
• the focus or scroll area does not move unexpectedly
• a form does not get submitted
• new windows or tabs are not opened unexpectedly

These behaviours can be acceptable as long as users are advised in text before the triggering element.

You will often need to make a judgement call based on the whole context of a page.

Mobile app testing

Use an external keyboard.