code: function(e) {
          var y = Event.getPageY(e);
  
          if (y < this.lastY) {
              this.goingUp = true;
          } else if (y > this.lastY) {
              this.goingUp = false;
          }
  
          this.lastY = y;
      }
docs: Keep track of the direction of the drag for use during onDragOver