code: function() {
  
          var activeElement = this.__activeElement;
          var now = getActiveElement();
          var isBlur = arguments[0];
          var node = this.node;
  
          if (isBlur !== false && node.contains(now)) {
              this.__focus(activeElement);
          }
  
          this.__autofocus = false;
          removeClass(node, this.__name('focus'));
  
          return this;
      }
docs: 让浮层失去焦点。将焦点退还给之前的元素，照顾视力障碍用户