code: function (state) {
  
              if (typeof state === 'boolean') {
                  return state ? this.show() : this.hide();
              }
              this.each(function () {
                  if (isHidden(this)) {
                      showHide(this, true);
                  } else {
                      showHide(this);
                  }
              });
              return this;
          }
docs: 显示隐藏互转
  @param state
  @returns {*}