--- a/netwerk/test/unit/test_header_Accept-Language.js
+++ b/netwerk/test/unit/test_header_Accept-Language.js
@@ -1,12 +1,17 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
 //
 //  HTTP Accept-Language header test
 //
 
+"use strict";
 Cu.import("resource://gre/modules/NetUtil.jsm");
 
 var testpath = "/bug672448";
 
 function run_test() {
   let intlPrefs = Cc["@mozilla.org/preferences-service;1"].getService(Ci.nsIPrefService).getBranch("intl.");
 
   // Save old value of preference for later.
@@ -40,21 +45,21 @@ function test_accepted_languages() {
 
   let AcceptLanguage = channel.getRequestHeader("Accept-Language");
 
   let acceptedLanguages = AcceptLanguage.split(",");
 
   let acceptedLanguagesLength = acceptedLanguages.length;
 
   for (let i = 0; i < acceptedLanguagesLength; i++) {
-    let acceptedLanguage, qualityValue;
+    let acceptedLanguage, qualityValue, unused;
 
     try {
       // The q-value must conform to the definition in HTTP/1.1 Section 3.9.
-      [_, acceptedLanguage, qualityValue] = acceptedLanguages[i].trim().match(/^([a-z0-9_-]*?)(?:;q=(1(?:\.0{0,3})?|0(?:\.[0-9]{0,3})))?$/i);
+      [unused, acceptedLanguage, qualityValue] = acceptedLanguages[i].trim().match(/^([a-z0-9_-]*?)(?:;q=(1(?:\.0{0,3})?|0(?:\.[0-9]{0,3})))?$/i);
     } catch(e) {
       do_throw("Invalid language tag or quality value: " + e);
     }
 
     if (i == 0) {
       // The first language shouldn't have a quality value.
       do_check_eq(qualityValue, undefined);
     } else {