code: function( y ){
  
          if( !this.scroll ) return;
  
          y = y < 0 ? 0 : y;
          y = y > this.range ? this.range : y;
  
          this.listIn.style.top = -Math.floor( y / this.ratio )+'px';
          this.scroller.style.top = Math.floor( y )  + 'px';
  
          this.py = y;
  
      }
docs: ----- LIST