Force Touch events

Non-standard: This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.

Force Touch events are a proprietary, Apple-specific feature which makes possible (where supported by the input hardware) new interactions based on how hard the user clicks or presses down on the touchscreen or trackpad.

Events

webkitmouseforcewillbegin: This event is fired before the mousedown event. Its main use is that it can be Event.preventDefault()ed.
webkitmouseforcedown: This event is fired after the mousedown event as soon as sufficient pressure has been applied for it to qualify as a "force click".
webkitmouseforceup: This event is fired after the webkitmouseforcedown event as soon as the pressure has been reduced sufficiently to end the "force click".
webkitmouseforcechanged: This event is fired each time the amount of pressure changes. This event first fires after the mousedown event and stops firing before the mouseup event.

Event properties

The following property is known to be available on the webkitmouseforcewillbegin, mousedown, webkitmouseforcechanged, webkitmouseforcedown, webkitmouseforceup, mousemove, and mouseup event objects:

MouseEvent.webkitForce Read only: The amount of pressure currently being applied to the trackpad/touchscreen

Constants

These constants are useful for determining the relative intensity of the pressure indicated by MouseEvent.webkitForce:

MouseEvent.WEBKIT_FORCE_AT_MOUSE_DOWN Read only: Minimum force necessary for a normal click
MouseEvent.WEBKIT_FORCE_AT_FORCE_MOUSE_DOWN Read only: Minimum force necessary for a force click

Specifications

Not part of any specification. Apple has a description at the Mac Developer Library.