Only fire smallscreen nav script if there is a nav.

templates/2k11/admin/serendipity_editor.js.tpl

@@ -1045,6 +1045,9 @@ var AccessifyHTML5 = function (defaults, more_fixes) {
 
 (function($) {
     // Fire responsive nav
+    var $hasMenu = $('body').has('#main_menu');
+
+    if($hasMenu.size() > 0) { 
         var navigation = responsiveNav('#main_menu', { 
             animate: true,          // Boolean: Use CSS3 transitions, true or false
             transition: 250,        // Integer: Speed of the transition, in milliseconds
@@ -1059,6 +1062,7 @@ var AccessifyHTML5 = function (defaults, more_fixes) {
             open: function() { } ,  // Function: Open callback
             close: function() { }   // Function: Close callback
         });
+    }
 
     // Fire WYSIWYG editor(s)
     serendipity.spawn();