diff --git a/templates/default/fulldoc/html/frames.erb b/templates/default/fulldoc/html/frames.erb
index bd9299949..c4569ccf0 100644
--- a/templates/default/fulldoc/html/frames.erb
+++ b/templates/default/fulldoc/html/frames.erb
@@ -5,13 +5,14 @@
 	<title><%= options.title %></title>
 </head>
 <script type="text/javascript">
+var mainUrl = '<%= url_for_main %>'
 try {
     var match = decodeURIComponent(window.location.hash).match(/^#!(.+)/);
-    var name = match ? match[1] : '<%= url_for_main %>';
+    var name = match ? match[1] : mainUrl;
     var url = new URL(name, location.href);
-    window.top.location.replace(url.origin === location.origin ? name : '<%= url_for_main %>');
+    window.top.location.replace(url.origin === location.origin ? name : mainUrl);
 } catch (e) {
-    window.top.location.replace('<%= url_for_main %>');
+    window.top.location.replace(mainUrl);
 }
 </script>
 <noscript>