diff --git a/assets/main.js b/assets/main.js
index 235899e..ee13bf9 100644
--- a/assets/main.js
+++ b/assets/main.js
@@ -1,7 +1,10 @@
-const pdfPreview = document.querySelector("iframe");
+(function fixPdfOverflow() {
+  const pdfPreview = document.querySelector("iframe");
 
-if (pdfPreview) {
-	pdfPreview.onload = function () {
-		pdfPreview.contentWindow.document.body.style.overflow = "hidden";
-	};
-}
+  if (!pdfPreview) {
+    return;
+  }
+  pdfPreview.onload = function () {
+    pdfPreview.contentWindow.document.body.style.overflow = "hidden";
+  };
+})();