vertical-enable.iscroll.js

var point, pointStartX, pointStartY, deltaX, deltaY;
var scroller = new iScroll('scrollerId', {
    vScroll: false,
    vScrollbar: false,
    hScrollbar: false,
    snap: 'li',
    momentum: false,
    onBeforeScrollStart: function(e) {
        point = e.touches[0];
        pointStartX = point.pageX;
        pointStartY = point.pageY;
        null;
    },
    onBeforeScrollMove: function(e) {
        deltaX = Math.abs(point.pageX - pointStartX);
        deltaY = Math.abs(point.pageY - pointStartY);
        if (deltaX >= deltaY) {
            e.preventDefault();
        } else {
            null;
        }
    }
});