diff --git a/web/app.js b/web/app.js
index 880cb43d8..821bf29ce 100644
--- a/web/app.js
+++ b/web/app.js
@@ -2178,14 +2178,14 @@ const PDFViewerApplication = {
   },
 };
 
-let validateFileURL;
 if (typeof PDFJSDev === "undefined" || PDFJSDev.test("GENERIC")) {
   const HOSTED_VIEWER_ORIGINS = [
     "null",
     "http://mozilla.github.io",
     "https://mozilla.github.io",
   ];
-  validateFileURL = function (file) {
+  // eslint-disable-next-line no-var
+  var validateFileURL = function (file) {
     if (!file) {
       return;
     }