files/en-us/web/api/pointerevent/pointerid/index.md
{{ APIRef("Pointer Events") }}
The pointerId read-only property of the {{domxref("PointerEvent")}} interface
is an identifier assigned to the pointer that triggered the event. The identifier
is unique, being different from the identifiers of all other active pointer events.
A value -1 indicates that the PointerEvent was not generated by a pointing device.
(For example, a {{domxref("Element/click_event", "click")}} event fired on a button
activated via keyboard.) Otherwise, the value may be randomly generated and should
not be relied on to convey any specific information about the device. The value is
only guaranteed to be stable for the lifetime of the page or session.
[!NOTE] The
pointerIdproperty is implemented inconsistently across browsers and does not always persist for each ink stroke or interaction with the screen. For a reliable way of identifying multiple pointing devices on a screen simultaneously, see {{domxref("PointerEvent.persistentDeviceId")}}.
A number.
The following code snippet compares a previously saved pointerId with the
one of the {{domxref("Element/pointerdown_event", "pointerdown")}} event that was just fired.
let id; // Let's assume that this is a previously saved pointerId
target.addEventListener("pointerdown", (event) => {
// Compare previous event's ID that was cached
// to current event's ID and handle accordingly
if (id === event.pointerId) process_event(event);
});
{{Specifications}}
{{Compat}}