function isBookmarkNode( node )
		{
			return ( node && node.getName
					&& node.getName() == 'span'
					&& node.hasAttribute('_fck_bookmark') );
		}
Whether the to-be-evaluated node is a bookmark node OR bookmark node
inner contents.
@param {Boolean} contentOnly Whether only test againt the text content of
bookmark node instead of the element itself(default).
@param {Boolean} isReject Whether should return 'false' for the bookmark
node instead of 'true'(default).