This technique applies to platforms where touch screen access is provided. It addresses interactive content where the user can perform one or more actions. The technique is applicable even when access to an action via a physical keyboard interaction is present.
Failure of 2.5.3 (new mobile SC)
This technique is applicable on platforms that support touch screen access where use of the touch screen is modified when platform assistive technology is active and the assistive technology supports access to the touch screen through a keyboard interface.
The objective of this technique is to ensure that interactions and functionality performed by persons who don't use assistive technology can also be performed using touch gestures by those who rely on platform assistive technology. It allows users of assistive technology to work in a mobile context without having to connect a physical keyboard.
On mobile platforms it is usually not practical or possible for users to carry around a physical keyboard. Users of assistive technology, such as those who are blind or visually impaired, rely on touch screens in a mobile context. Screen readers work with touch interfaces, but they can remap some of the standard OS touch gestures. They do this so the user can discover and/or select items on the screen without activating them.
Platform assistive technology is built into the operating system and is generally updated through OS updates. Examples include VoiceOver on iOS and TalkBack on Android.
Failure example 1 demonstrates how a touch gesture is created that is not sent to the user agent when platform assistive technology runs that modifies the touch interface and no alternative touch gesture or touch accessible control is provided.
A carousel control is provided to display multiple interactive items in a horizontal scrolling area. The user can scroll the carousel by swiping left or right with one finger. Swiping right moves the displayed carousel items right exposing previous items in the carousel and swiping left moves the displayed carousel items left expose the next items in the carousel. When platform assistive technology such as a screen reader is active, swiping left and right are used by the screen reader to focus the previous or next items respectively. Screen specific commands such as three finger left and right swipes are not recognized by the carousel. There are no other on-screen controls to control the carousel. Items in the carousel respond to single taps to view that item or when platform assistive technology such as a screen reader are running a double tap of the carousel item allows the user to view the item as expected.
Failure example 2 demonstrates how touch events can be used to trigger an action without using an equivalent device independent method without another alternative method being available to interact with the control.
A button uses touch start and touch end events to determine that the user has tapped a button with a single tap gesture. There is no other way to activate the button.
A web page has an infinite scroll that populates the bottom of the page as the user swipes up to scroll the new inserted content into view. When the screen reader is turned on, the up swipe is used by the reader to select the item above the focus. The screen reader remaps a three finger swipe to scroll upwards. However, on this web page neither of those actions will activate the infinite scroll functionality of the page. There is no other way to scroll the page so that new content populates the page with touch or gesture when the screen reader is turned on, so a user who is blind cannot use this page in a mobile context.
Test that for each interactive element that responds to touch or gesture all content is available when platform assistive technology is enabled that changes the touch interaction mode; or there is equivalent functionality provided