Index: typo3/js/clickmenu.js
===================================================================
--- typo3/js/clickmenu.js	(revision 6314)
+++ typo3/js/clickmenu.js	(working copy)
@@ -71,7 +71,9 @@
 				}.bind(this)
 			});
 		} else { // fallback with no AJAX, no isCMLayers
-			top.loadTopMenu(this.clickURL + '?' + params);
+			if ('function' === typeof top.loadTopMenu) {
+				top.loadTopMenu(this.clickURL + '?' + params);
+			}
 		}
 	},