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

This solution takes into account change in directions which the current answers does not. The solution below also takes care of touch sensitivity; this when the user is moving in one direction but on touch end the users finger nudges in a different direction messing up the actual direction.

 var y = 0; //current y pos
 var sy = y; //previous y pos
 var error = 5; //touch sensitivity, I found between 4 and 7 to be good values. 

 function move(e) {
    //get current y pos
    y = e.pageY;

    //ingnore user jitter
    if (Math.abs(y - sy) > error) {
        //find direction of y
        if (y > sy) {
            //move down 
        } else {
            //move up
        }
        //store current y pos
        sy = y;
    }
}