code: function()
  		{
  			var ranges = this.getRanges(),
  				startNode = ranges[ 0 ].startContainer,
  				endNode = ranges[ ranges.length - 1 ].endContainer;
  			return startNode.getCommonAncestor( endNode );
  		}
docs: Retrieves the common ancestor node of the first range and the last range.
  @returns {CKEDITOR.dom.element} The common ancestor of the selection.
  @example
  var ancestor = editor.getSelection().<strong>getCommonAncestor()</strong>;