--- loncom/interface/lonhtmlcommon.pm	2021/06/07 06:15:55	1.399
+++ loncom/interface/lonhtmlcommon.pm	2021/10/26 02:31:22	1.400
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # a pile of common html routines
 #
-# $Id: lonhtmlcommon.pm,v 1.399 2021/06/07 06:15:55 raeburn Exp $
+# $Id: lonhtmlcommon.pm,v 1.400 2021/10/26 02:31:22 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -3433,12 +3433,18 @@ PARAMSONE
         if (itemid != null) {
             itemh = itemid.offsetHeight;
         }
-        var primaryheight = document.getElementById('LC_nav_bar').offsetHeight;
-        var secondaryheight;
+        var primaryheight = 0;
+        if (document.getElementById('LC_nav_bar') != null) { 
+            primaryheight = document.getElementById('LC_nav_bar').offsetHeight;
+        }
+        var secondaryheight = 0;
         if (document.getElementById('LC_secondary_menu') != null) { 
             secondaryheight = document.getElementById('LC_secondary_menu').offsetHeight;
         }
-        var crumbsheight = document.getElementById('LC_breadcrumbs').offsetHeight;
+        var crumbsheight = 0;
+        if (document.getElementById('LC_breadcrumbs') != null) {
+            crumbsheight = document.getElementById('LC_breadcrumbs').offsetHeight;
+        }
         var dccidheight = 0;
         if (document.getElementById('dccid') != null) {
             dccidheight = document.getElementById('dccid').offsetHeight;