diff --git a/extensions/firefox/content/PdfJs-stub.jsm b/extensions/firefox/content/PdfJs-stub.jsm
index 5d8548bed..ad64a1416 100644
--- a/extensions/firefox/content/PdfJs-stub.jsm
+++ b/extensions/firefox/content/PdfJs-stub.jsm
@@ -1,3 +1,5 @@
+/* -*- Mode: Java; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set shiftwidth=2 tabstop=2 autoindent cindent expandtab: */
 /* Copyright 2012 Mozilla Foundation
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -12,10 +14,13 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+/* jshint esnext:true, maxlen:100 */
+
+'use strict';
 
 // Don't remove this file. FF15+ expects PdfJs module to be present at resource://pdf.js/PdfJs.jsm
 // See https://mxr.mozilla.org/mozilla-central/source/browser/components/nsBrowserGlue.js
-var EXPORTED_SYMBOLS = ["PdfJs"];
+var EXPORTED_SYMBOLS = ['PdfJs'];
 
 let PdfJs = {
   init: function PdfJs_init() {}