Determine vertical direction of a touchmove

Question

i\'m trying to implement a touch listener for tablets to trigger some actions depending whether it touchmoved upwards or downwards.

I tried the native listener:

Answer 1

You need to save the last position of the touch, then compare it to the current one.
Rough example:

var lastY;
$(document).bind('touchmove', function (e){
     var currentY = e.originalEvent.touches[0].clientY;
     if(currentY > lastY){
         // moved down
     }else if(currentY < lastY){
         // moved up
     }
     lastY = currentY;
});