diff --git a/charsets.js b/charsets.js
index 59fcdf5cf..7f54ab327 100644
--- a/charsets.js
+++ b/charsets.js
@@ -1,3 +1,7 @@
+/* -*- Mode: Java; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set shiftwidth=2 tabstop=2 autoindent cindent expandtab: */
+
+'use strict';
 
 var ISOAdobeCharset = [
   '.notdef', 'space', 'exclam', 'quotedbl', 'numbersign', 'dollar',
diff --git a/extensions/firefox/components/pdfContentHandler.js b/extensions/firefox/components/pdfContentHandler.js
index 879924047..9186bfd8a 100644
--- a/extensions/firefox/components/pdfContentHandler.js
+++ b/extensions/firefox/components/pdfContentHandler.js
@@ -131,8 +131,7 @@ pdfContentHandler.prototype = {
       throw Cr.NS_ERROR_WONT_HANDLE_CONTENT;
 
     let window = null;
-    let callbacks = aRequest.notificationCallbacks ?
-                    aRequest.notificationCallbacks :
+    let callbacks = aRequest.notificationCallbacks ||
                     aRequest.loadGroup.notificationCallbacks;
     if (!callbacks)
       return;