Understanding Success Criterion 2.5.7: Dragging

Success Criterion 2.5.7 Dragging (Level AA): All functionality that uses a dragging movement for operation can be operated by a single pointer without dragging, unless dragging is essential.

This requirement applies to web content that interprets pointer actions (i.e. this does not apply to actions that are required to operate the user agent or assistive technology).

Is there an assistive technology that helps for people with mobility impairments? The group would like feedback on the frontier between AT & author responsibility.

Status

This understanding document is part of the draft WCAG 2.2 content. It may change or be removed before the final WCAG 2.2 is published.

Intent

The intent of this Success Criterion is to ensure functionality that uses a dragging movement (e.g. sliders, drag-and-drop interfaces) has another single pointer mode of operation without the need for the dexterity required to drag elements.

Some people cannot perform dragging motions in a precise manner. Others use a specialized or adapted input device such as a head pointer, eye-gaze system, or speech-controlled mouse emulator, which makes dragging cumbersome, error-prone, or outright impossible.

When an interface implements functionality that uses dragging motions, some users can tap or click, but not accurately maintain contact whilst performing a dragging motion. An alternative method must be provided so that users with mobility impairments that use a pointer (mouse, pen, or touch contact) can use the functionality.

2.1.1 Keyboard and 2.1.3 Keyboard (No Exception) require dragging features to be keyboard accessible, however, it is possible to create an interface that works with dragging and keyboard controls that does not work using only clicks or taps.

A dragging movement is a pointer interaction where only the endpoints matter. Once the pointer engages with a target, the target (or a position mark related to the target) will follow the pointer regardless of the direction of the pointer movement. The target's movement may be constrained to one axis and often, to a particular range on that axis, but within those constraints, the x or y position of the target will mirror the corresponding x or y position of the pointer until the pointer disengages the target.

In contrast to dragging movements, path-based gestures involve at least an initial directionality of the pointer movement. This is defined by stating that the path has to go through at least one intermediate point to qualify as pointer gesture. The intermediate point defines the gesture as requiring a specific path, even if the complete path is not defined. For more details, refer to Understanding Success Criterion 2.5.1 Pointer Gestures.

Benefits

Examples

Techniques

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. However, it is not necessary to use these particular techniques. For information on using other techniques, see Understanding Techniques for WCAG Success Criteria, particularly the "Other Techniques" section.

Sufficient Techniques

  1. G219: Ensuring that a single pointer operable alternative is available for dragging movements that operate on content

Failures

The following are common mistakes that are considered failures of this Success Criterion by the WCAG Working Group.

Key Terms

dragging movement

an operation where the pointer engages with an element on the down event and the element (or a representation of its position) follows the pointer

Note

The element could be, for example, a list item, a text element, or an image.

essential

if removed, would fundamentally change the information or functionality of the content, and information and functionality cannot be achieved in another way that would conform