Functionality that can be operated by motion can also be operated by user interface components, and the motion trigger can be disabled. (Level A)

Rationale

Objective: Don’t rely solely on device motion to control page content

This checkpoint is intended to primarily benefit users who are unable to physically manipulate devices and those who inadvertently trigger motion features due to tremors. Where authors offer functionality that is triggered by motion, they must provide an alternative accessible means of operation and also provide an ability to disable motion as an interaction method.

An example of a motion actuation feature is a Shake To Undo feature. This could be made accessible by providing a user setting to disable it and offering an Undo button to provide the same action.

Spacial Exception: WCAG states: "This criterion concerns input through sensors which respond directly to motions such as gesturing towards, tilting or shaking a device. It does not cover the movement of users through space as registered by geolocation sensors or beacons."

Accessibility Supported Exception: Motion can be the sole means of operation where it triggers functionality through an accessibility supported interface, such as using eye movement detected by a camera as an alternative input device.

Essential Exception: This checkpoint does not apply where the motion is essential for the function, and disabling or bypassing it would invalidate the activity. A pedometer that relies on device motion to count steps is an example of such an essential activity.

IBM has simplified the normative language of this checkpoint. Refer to Understanding 2.5.4 (external link to WCAG) for more information.

Development Techniques

This paragraph appears generically in all checkpoints. 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

Any item in this section represents a technique deemed sufficient. Ensure you review WCAG Common Failures to avoid development mistakes.

Web (HTML, ARIA, CSS) techniques

In addition to the General techniques, any item in this section represents a technique deemed sufficient.

Mobile Native (iOS) techniques

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

Eclipse techniques

There are no specific Eclipse techniques for this checkpoint. Refer to the General techniques section.

Windows-based (MSAA+IA2) techniques

There are no specific Windows-based (MSAA+IA2) techniques for this checkpoint. Refer to the General techniques section.


Many links in this checklist reside outside ibm.com at the Web Content Accessibility Guidelines (WCAG) 2.1. W3C Recommendation 05 June 2018: http://www.w3.org/TR/WCAG21/

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