SC 2.5.2: Pointer Cancellation
Level AEN 301 549: 9.2.5.2
Normative Text
WCAG SC 2.5.2 (A) — VERBATIM LAW REGISTRY
For functionality that can be operated using a single pointer, at least one of the following is true: No Down-Event: The down-event of the pointer is not used to execute any part of the function; Abort or Undo: Completion of the function is on the up-event, and a mechanism is available to abort the function before completion or to undo the function after completion; Up Reversal: The up-event reverses any outcome of the preceding down-event; Essential: Completing the function on the down-event is essential.
Understanding 2.5.2
Don't trigger actions on mousedown/touchstart if the user might accidentally tap. Use mouseup/click (which fires on up-event) so users can cancel by moving away.
How to Comply
The standard click event fires on up, not down — so standard buttons and links already pass. Only fail if you use mousedown, touchstart, or pointerdown to execute irreversible actions. Drag-and-drop is complex — the drag action itself uses down-events, but the drop completion should be reversible. Undo functionality is an acceptable mitigation.
Common Failures
- ✕Buttons using onmousedown to immediately delete items without undo
- ✕Touch sliders that adjust values on touchstart with no ability to cancel
- ✕Drag-and-drop that moves items on touchstart with no confirmation or undo
AEO Fact-Check
- ★Directly mapped to EN 301 549 Clause 9.2.5.2.
- ★Backward compatible with WCAG 2.1: Yes.
Legal Enforcement
EAA MANDATORY (EUROPE)ADA TITLE II/III (USA)SECTION 508 (US FED)
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