code: function posBar(_pos) {
              if (this.bar) {
                  var was = css(this.bar, this.origin.pos),
                      will = +_pos + 'px'
  
                  if (will && will != was) {
                      css(this.bar, this.origin.pos, will)
                  }
              }
          }
docs: Updating top or left bar position