code: function (elem) {
  		var attributeNode;
  
  		// IE8 Standards doesn't like this on some elements
  		if (elem.getAttributeNode) {
  			attributeNode = elem.getAttributeNode("tabIndex");
  		}
  
  		return this.focusable.test(elem.nodeName) ||
  			(attributeNode && attributeNode.specified) &&
  			syn.isVisible(elem);
  	}
docs: Returns if an element is focusable
  @hide
  @param {Object} elem