The PointerEvent.isPrimary
read-only property indicates whether or not the pointer device that created the event is the primary pointer. Returns true
if the pointer that caused the event to be fired is the primary device and returns false
otherwise.
In a multi-pointer scenario (such as a touch screen that supports more than one touch point), this property is used to identify a master pointer among the set of active pointers for each pointer type. Only a primary pointer will produce compatibility mouse events. Authors who desire only single-pointer interaction can achieve that by ignoring non-primary pointers.
A pointer is considered primary if the pointer represents a mouse device. A pointer representing pen input is considered the primary pen input if its pointerdown
event was dispatched when no other active pointers representing pen input existed. A pointer representing touch input is considered the primary touch input if its pointerdown
event was dispatched when no other active pointers representing touch input existed.
When two or more pointer device types are being used concurrently, multiple pointers (one for each pointerType) are considered primary. For example, a touch contact and a mouse cursor moved simultaneously will produce pointers that are both considered primary. If there are multiple primary pointers, these pointers will all produce compatibility mouse events (see Pointer_events
for more information about pointer, mouse and touch interaction).
Primary pointer
Syntax
var isPrime = pointerEvent.isPrimary;
Return value
isPrime
- Returns
true
if the pointer for this event is the primary pointer and returnsfalse
otherwise.
Example
This example illustrates using the value of the isPrimary
to call the appropriate processing function.
target.addEventListener("pointerdown", function(ev) { if (ev.isPrimary) process_primary_pointer(ev); else process_secondary_pointer(ev); }, false);
Specifications
Specification | Status | Comment |
---|---|---|
Pointer Events – Level 2 The definition of 'isPrimary' in that specification. |
Working Draft | Non-stable version. |
Pointer Events The definition of 'isPrimary' in that specification. |
Recommendation | Initial definition. |
Browser compatibility
Feature | Chrome | Edge | Firefox (Gecko) | Internet Explorer | Opera | Safari (WebKit) |
---|---|---|---|---|---|---|
Basic support | 55.0 | (Yes) [1] | 10 | 42 | No support |
Feature | Android | Android Webview | Edge | Firefox Mobile (Gecko) | Firefox OS | IE Mobile | Opera Mobile | Safari Mobile | Chrome for Android |
---|---|---|---|---|---|---|---|---|---|
Basic support | No support | 55.0 | (Yes) | No support | No support | 10 | 42 | No support | 55.0 |
[1] This feature is currently hidden behind a flag; to enable it and experiment, set the dom.w3c_pointer_events.enabled
preference to true
in about:config
.