Touch
The Touch interface represents a single contact point on a touch-sensitive device. The contact point is commonly a finger or stylus and the device may be a touchscreen or trackpad.
Properties
The Touch.identifier returns a value uniquely identifying this point of contact with the touch surface. This value remains consistent for every event involving this finger's (or stylus's) movement on the surface until it is lifted off the surface.
The rotationAngle read-only property of the Touch interface returns the rotation angle, in degrees, of the contact area ellipse defined by Touch.radiusX and Touch.radiusY. The value may be between 0 and 90. Together, these three values describe an ellipse that approximates the size and shape of the area of contact between the user and the screen. This may be a relatively large ellipse representing the contact between a fingertip and the screen or a small area representing the tip of a stylus, for example.
The read-only target property of the Touch interface returns the (EventTarget) on which the touch contact started when it was first placed on the surface, even if the touch point has since moved outside the interactive area of that element or even been removed from the document. Note that if the target element is removed from the document, events will still be targeted at it, and hence won't necessarily bubble up to the window or document anymore. If there is any risk of an element being removed while it is being touched, the best practice is to attach the touch listeners directly to the target.