Add and expose screen touch events

src/Browser/Events.elm

@@ -2,6 +2,7 @@ effect module Browser.Events where { subscription = MySub } exposing
   ( onAnimationFrame, onAnimationFrameDelta
   , onKeyPress, onKeyDown, onKeyUp
   , onClick, onMouseMove, onMouseDown, onMouseUp
+  , onTouchStart, onTouchEnd, onTouchCancel, onTouchMove
   , onResize, onVisibilityChange, Visibility(..)
   )
 
@@ -30,6 +31,10 @@ If there is something else you need, use [ports] to do it in JavaScript!
 @docs onClick, onMouseMove, onMouseDown, onMouseUp
 
 
+# Touchscreen
+
+@docs onTouchStart, onTouchEnd, onTouchCancel, onTouchMove
+
 # Window
 
 @docs onResize, onVisibilityChange, Visibility
@@ -176,6 +181,33 @@ onMouseUp : Decode.Decoder msg -> Sub msg
 onMouseUp =
   on Document "mouseup"
 
+-- TOUCHSCREEN
+
+{-| Subscribe to touch start events anywhere on screen.
+-}
+onTouchStart : Decode.Decoder msg -> Sub msg
+onTouchStart =
+  on Document "touchstart"
+
+
+{-| Subscribe to touch end events anywhere on screen.
+-}
+onTouchEnd : Decode.Decoder msg -> Sub msg
+onTouchEnd =
+  on Document "touchend"
+
+{-| Subscribe to touch cancel events anywhere on screen.
+-}
+onTouchCancel : Decode.Decoder msg -> Sub msg
+onTouchCancel =
+  on Document "touchcancel"
+
+{-| Subscribe to touch movement events anywhere on screen.
+-}
+onTouchMove : Decode.Decoder msg -> Sub msg
+onTouchMove =
+  on Document "touchmove"
+
 
 
 -- WINDOW