diff --git a/static/js/cours.js b/static/js/cours.js
index 74459a2..abc754a 100644
--- a/static/js/cours.js
+++ b/static/js/cours.js
@@ -148,14 +148,17 @@ window.addEventListener("load", () => {
   dataElement.remove();
 
   // Open nested openeded directories
-  const fullpath = window.location.href.split("?")[1].substring(2);
-  const path = fullpath.substring(0, fullpath.lastIndexOf("/"));
-  const last_openeded = deepestNodeOpened(
-    path.split("/"),
-    fileTreeElement.querySelector("ul").childNodes
-  );
+  const infoURL = window.location.href.split("?");
+  if (infoURL.length > 1) {
+    const fullpath = infoURL[1].substring(2);
+    const path = fullpath.substring(0, fullpath.lastIndexOf("/"));
+    const last_openeded = deepestNodeOpened(
+      path.split("/"),
+      fileTreeElement.querySelector("ul").childNodes
+    );
 
-  uncollapse(last_openeded);
+    uncollapse(last_openeded);
+  }
 
   // Fix SVG images
   svgDarkTheme();