More tweaks to get to work if no nav

diff --git a/js/game.js b/js/game.js
index a34c312..994e429 100644
--- a/js/game.js
+++ b/js/game.js
@@ -531,6 +531,9 @@ class Location
         const content_areas = ["main-nav", "game-content"];
         for (const content_area of content_areas) {
             let content = elt(content_area);
+            if (!content) {
+                continue;
+            }
             if (content_area == 'main-nav') {
                 if (!content.hasOwnProperty("originalHTML")) {
                     content.originalHTML = content.innerHTML;