Dev: Remove use of getRootNode() its a new method that don't appear to

work well across browsers.

- Using two different methods now - check that the node is in the body
  using a little jQuery
- And that there are actually rows in the table

js/dataTables.keyTable.js

@@ -248,11 +248,15 @@ $.extend( KeyTable.prototype, {
 
 			var lastFocus = that.s.lastFocus;
 
-			if ( lastFocus && lastFocus.node.getRootNode() === document ) {
+			if ( lastFocus && lastFocus.node && $(lastFocus.node).closest('body') === document.body ) {
 				var relative = that.s.lastFocus.relative;
 				var info = dt.page.info();
 				var row = relative.row + info.start;
 
+				if ( info.recordsDisplay === 0 ) {
+					return;
+				}
+
 				// Reverse if needed
 				if ( row >= info.recordsDisplay ) {
 					row = info.recordsDisplay - 1;