PointerEvent

PointerEvent is a DOM event interface representing input from pointing devices such as a mouse, pen, or touch. It is part of the Pointer Events API, a W3C standard designed to unify input handling across device types and to provide more detailed data about the contact point. PointerEvent objects are dispatched by the browser in response to pointer events such as pointerdown, pointermove, pointerup, and pointercancel, as well as pointerover, pointerout, pointerenter, and pointerleave.

Core properties include pointerId (a unique identifier for the contact), pointerType ("mouse", "pen", or "touch"), isPrimary (true if this is the primary contact for the pointer), width and height (contact area), pressure (0..1), tiltX and tiltY (stylus tilt), and tangentialPressure. These fields enable richer interpretation of user input and can be used to adapt interactions to the input method.

The API also exposes methods for accessing historical data, such as getCoalescedEvents() (returns an array of coalesced PointerEvent objects that occurred between frames) and getPredictedEvents() (returns predicted upcoming events to smooth rendering on high-latency devices).

Pointer events support advanced features like pointer capture, where an element can call setPointerCapture(pointerId) to receive all subsequent events for that contact until releasePointerCapture(pointerId). This helps maintain consistent interaction even if the pointer moves outside the initial element.

Common events include pointerdown, pointermove, pointerup, and pointercancel, along with pointerover, pointerout, pointerenter, and pointerleave. Pointer Events originated from MSPointer events and were standardized to provide a single model for mouse, touch, and pen input, widely supported in modern browsers. They are recommended for interactive web applications requiring multi-device input.