diff --git a/static/skin/viewer.js b/static/skin/viewer.js
index f9d9f3bbc..d4eeed8b8 100644
--- a/static/skin/viewer.js
+++ b/static/skin/viewer.js
@@ -30,7 +30,7 @@ function getBookFromUserUrl(url) {
   return url.split('/')[0];
 }
 
-let currentBook = getBookFromUserUrl(location.hash.slice(1));
+let currentBook = null;
 let currentBookTitle = null;
 
 const bookUIGroup = document.getElementById('kiwix_serve_taskbar_book_ui_group');
@@ -291,17 +291,15 @@ function setup_external_link_blocker() {
 // End of external link blocking
 ////////////////////////////////////////////////////////////////////////////////
 
+let viewerSetupComplete = false;
+
 function on_content_load() {
-  handle_content_url_change();
-  setup_external_link_blocker();
+  if ( viewerSetupComplete ) {
+    handle_content_url_change();
+    setup_external_link_blocker();
+  }
 }
 
-window.onresize = handle_visual_viewport_change;
-window.onhashchange = handle_location_hash_change;
-
-updateCurrentBook(currentBook);
-handle_location_hash_change();
-
 function htmlDecode(input) {
     var doc = new DOMParser().parseFromString(input, "text/html");
     return doc.documentElement.textContent;
@@ -397,6 +395,8 @@ function setupViewer() {
   // has been settled.
   setTimeout(handle_visual_viewport_change, 0);
 
+  window.onresize = handle_visual_viewport_change;
+
   const kiwixToolBarWrapper = document.getElementById('kiwixtoolbarwrapper');
   if ( ! viewerSettings.toolbarEnabled ) {
     return;
@@ -417,4 +417,12 @@ function setupViewer() {
   if (document.body.clientWidth < 520) {
     setupAutoHidingOfTheToolbar();
   }
+
+  currentBook = getBookFromUserUrl(location.hash.slice(1));
+  updateCurrentBook(currentBook);
+  handle_location_hash_change();
+
+  window.onhashchange = handle_location_hash_change;
+
+  viewerSetupComplete = true;
 }
diff --git a/test/server.cpp b/test/server.cpp
index a68ea3356..5c07b540e 100644
--- a/test/server.cpp
+++ b/test/server.cpp
@@ -69,7 +69,7 @@ const ResourceCollection resources200Compressible{
   { DYNAMIC_CONTENT, "/ROOT/skin/taskbar.css" },
   { STATIC_CONTENT,  "/ROOT/skin/taskbar.css?cacheid=216d6b5d" },
   { DYNAMIC_CONTENT, "/ROOT/skin/viewer.js" },
-  { STATIC_CONTENT,  "/ROOT/skin/viewer.js?cacheid=ab5374c5" },
+  { STATIC_CONTENT,  "/ROOT/skin/viewer.js?cacheid=33265688" },
   { DYNAMIC_CONTENT, "/ROOT/skin/fonts/Poppins.ttf" },
   { STATIC_CONTENT,  "/ROOT/skin/fonts/Poppins.ttf?cacheid=af705837" },
   { DYNAMIC_CONTENT, "/ROOT/skin/fonts/Roboto.ttf" },
@@ -294,7 +294,7 @@ R"EXPECTEDRESULT(                                <img src="../skin/download.png?
       /* url */ "/ROOT/viewer",
 R"EXPECTEDRESULT(    <link type="text/css" href="./skin/taskbar.css?cacheid=216d6b5d" rel="Stylesheet" />
     <link type="text/css" href="./skin/css/autoComplete.css?cacheid=08951e06" rel="Stylesheet" />
-    <script type="text/javascript" src="./skin/viewer.js?cacheid=ab5374c5" defer></script>
+    <script type="text/javascript" src="./skin/viewer.js?cacheid=33265688" defer></script>
     <script type="text/javascript" src="./skin/autoComplete.min.js?cacheid=1191aaaf"></script>
       const blankPageUrl = root + "/skin/blank.html?cacheid=6b1fa032";
           <label for="kiwix_button_show_toggle"><img src="./skin/caret.png?cacheid=22b942b4" alt=""></label>