Understanding Success Criterion 2.5.7: Dragging Movements

Success Criterion 2.5.7 Dragging Movements (Level AA): All functionality that uses a dragging movement for operation can be achieved 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.

Success Criteria 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.

This Success Criterion applies to dragging motions as opposed to pointer gestures, which are covered in Success Criterion 2.5.1 Pointer Gestures. Pointer gestures include directional path-based as well as multi-point gestures. In contrast, for dragging motions, only the start and end point of the motion matters, not the actual path.

There may be cases where a dragging movement is essential, for example, drawing a freeform figure, or playing a game where the aim is to follow a particular track as accurately as possible. The criterion has an exception for these cases where the task requires dragging.

Some tasks may typically involve dragging, such as sorting items in a list, but as there are other ways to achieve that task they are not considered essential.

Dragging movements covered in this Success Criterion are pointer interactions where only the endpoints matter. Once the pointer engages with a target, the direction of the dragging motion does not factor into the interaction until the pointer disengages the target. Since the dragging movement does not have an intermediate point, the dragging motion can go in any direction.

Path-based gestures covered in Success Criterion 2.5.1 Pointer Gestures are pointer interactions that involve at least an initial directionality. The pointer motion must include at least one intermediate point to qualify as a path-based gesture. The intermediate point defines the motion as a gesture by requiring a specific path, even when the entire path to complete the interaction is not predefined. While a user may use dragging movements to perform the interaction, path-based gestures requires following a path to an intermediate point. 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