Experimental support for touch events is added in Gecko 2.0. These allow you to track the movement of the user's finger on a touch screen, monitoring the raw touch events generated by the system. Although touch events are based on — and work similarly to — mouse events, each event includes an identifier that allows you to track multiple fingers moving on the screen at the same time.
Touch events are based upon mouse events, and thereby share all mouse event fields. They include one additional field.
A unique integer identifying the finger generating the event. When the
MozTouchDownevent is built, a unique value is assigned to that finger. Corresponding
MozTouchUpevents for that finger will have the same streamId value. This lets you track each finger's movements on the touch screen independently. The stream ID is unique until the
MozTouchUpevent occurs; after that, the value may be recycled for another series of events.
Types of touch events
Sent when the user beings a screen touch action.
Sent when the user moves his finger on the touch screen.
Sent when the user lifts his finger off the screen.