diff --git a/browser/base/content/syncSetup.js b/browser/base/content/syncSetup.js
index 8fdf68d94f09..7d3794459815 100644
--- a/browser/base/content/syncSetup.js
+++ b/browser/base/content/syncSetup.js
@@ -880,9 +880,9 @@ var gSyncSetup = {
   // if no property string is passed in, we clear label/style
   _setFeedback: function (element, success, string) {
     element.hidden = success || !string;
-    let class = success ? "success" : "error";
+    let classname = success ? "success" : "error";
     let image = element.getElementsByAttribute("class", "statusIcon")[0];
-    image.setAttribute("status", class);
+    image.setAttribute("status", classname);
     let label = element.getElementsByAttribute("class", "status")[0];
     label.value = string;
   },
diff --git a/browser/fuel/src/fuelApplication.js b/browser/fuel/src/fuelApplication.js
index d64035f908cc..6310af5501b5 100644
--- a/browser/fuel/src/fuelApplication.js
+++ b/browser/fuel/src/fuelApplication.js
@@ -703,10 +703,10 @@ Application.prototype = {
 
   get windows() {
     var win = [];
-    var enum = Utilities.windowMediator.getEnumerator("navigator:browser");
+    var browserEnum = Utilities.windowMediator.getEnumerator("navigator:browser");
 
-    while (enum.hasMoreElements())
-      win.push(new Window(enum.getNext()));
+    while (browserEnum.hasMoreElements())
+      win.push(new Window(browserEnum.getNext()));
 
     return win;
   },
diff --git a/docshell/test/chrome/bug449778_window.xul b/docshell/test/chrome/bug449778_window.xul
index 3873f5a25873..dd311997ecd2 100644
--- a/docshell/test/chrome/bug449778_window.xul
+++ b/docshell/test/chrome/bug449778_window.xul
@@ -9,8 +9,8 @@
   <!-- test code goes here -->
   <script type="application/javascript"><![CDATA[
     var imports = [ "SimpleTest", "is", "isnot", "ok", "onerror" ];
-    for each (var import in imports) {
-      window[import] = window.opener.wrappedJSObject[import];
+    for each (var name in imports) {
+      window[name] = window.opener.wrappedJSObject[name];
     }
 
     function $(id) {
diff --git a/docshell/test/chrome/bug449780_window.xul b/docshell/test/chrome/bug449780_window.xul
index 187fd34f33b3..5733f93d61f8 100644
--- a/docshell/test/chrome/bug449780_window.xul
+++ b/docshell/test/chrome/bug449780_window.xul
@@ -9,8 +9,8 @@
   <!-- test code goes here -->
   <script type="application/javascript"><![CDATA[
     var imports = [ "SimpleTest", "is", "isnot", "ok", "onerror" ];
-    for each (var import in imports) {
-      window[import] = window.opener.wrappedJSObject[import];
+    for each (var name in imports) {
+      window[name] = window.opener.wrappedJSObject[name];
     }
 
     function $(id) {
diff --git a/layout/base/tests/chrome/chrome_content_integration_window.xul b/layout/base/tests/chrome/chrome_content_integration_window.xul
index f85e9ef60404..2ba9e9024245 100644
--- a/layout/base/tests/chrome/chrome_content_integration_window.xul
+++ b/layout/base/tests/chrome/chrome_content_integration_window.xul
@@ -21,8 +21,8 @@
   <script type="application/javascript">
     <![CDATA[
     var imports = [ "SimpleTest", "is", "isnot", "ok" ];
-    for each (var import in imports) {
-      window[import] = window.opener.wrappedJSObject[import];
+    for each (var name in imports) {
+      window[name] = window.opener.wrappedJSObject[name];
     }
     
     function runTests() {
diff --git a/layout/base/tests/chrome/chrome_over_plugin_window.xul b/layout/base/tests/chrome/chrome_over_plugin_window.xul
index b9792447c8b6..4e167ed10e14 100644
--- a/layout/base/tests/chrome/chrome_over_plugin_window.xul
+++ b/layout/base/tests/chrome/chrome_over_plugin_window.xul
@@ -22,8 +22,8 @@
   <script type="application/javascript">
     <![CDATA[
     var imports = [ "SimpleTest", "is", "isnot", "ok", "todo" ];
-    for each (var import in imports) {
-      window[import] = window.opener.wrappedJSObject[import];
+    for each (var name in imports) {
+      window[name] = window.opener.wrappedJSObject[name];
     }
 
     var plugin;
diff --git a/layout/base/tests/chrome/default_background_window.xul b/layout/base/tests/chrome/default_background_window.xul
index a87d675cb517..8e6b5f91da6e 100644
--- a/layout/base/tests/chrome/default_background_window.xul
+++ b/layout/base/tests/chrome/default_background_window.xul
@@ -18,8 +18,8 @@
     SimpleTest.waitForExplicitFinish();
 
     var imports = [ "SimpleTest", "is", "isnot", "ok" ];
-    for each (var import in imports) {
-      window[import] = window.opener.wrappedJSObject[import];
+    for each (var name in imports) {
+      window[name] = window.opener.wrappedJSObject[name];
     }
     
     function snapshot(win) {
diff --git a/layout/style/test/chrome/hover_helper.html b/layout/style/test/chrome/hover_helper.html
index ca063dcb22f4..9f9680597ce0 100644
--- a/layout/style/test/chrome/hover_helper.html
+++ b/layout/style/test/chrome/hover_helper.html
@@ -36,8 +36,8 @@
 <script type="application/javascript">
 
 var imports = [ "SimpleTest", "is", "isnot", "ok" ];
-for each (var import in imports) {
-    window[import] = window.opener.wrappedJSObject[import];
+for each (var name in imports) {
+    window[name] = window.opener.wrappedJSObject[name];
 }
 
 var div = document.getElementById("display");
diff --git a/testing/mochitest/browser-harness.xul b/testing/mochitest/browser-harness.xul
index bff8db237c91..a834ed8087ce 100644
--- a/testing/mochitest/browser-harness.xul
+++ b/testing/mochitest/browser-harness.xul
@@ -204,8 +204,8 @@
         }
         var path = _entityEncode(this.path);
         var html = this.results.map(function (t) {
-          var class = t.info ? "info" : "result " + (t.pass ? "passed" : "failed");
-          return "<p class=\"" + class + "\">" + t.result + " | " + path +
+          var classname = t.info ? "info" : "result " + (t.pass ? "passed" : "failed");
+          return "<p class=\"" + classname + "\">" + t.result + " | " + path +
                  " | " + _entityEncode(t.msg) + "</p>";
         }).join("\n");
         if (this.duration) {
diff --git a/toolkit/content/tests/chrome/bug263683_window.xul b/toolkit/content/tests/chrome/bug263683_window.xul
index 44b380258b90..2cb37a065e3e 100644
--- a/toolkit/content/tests/chrome/bug263683_window.xul
+++ b/toolkit/content/tests/chrome/bug263683_window.xul
@@ -55,8 +55,8 @@
     var gBrowser;
 
     var imports = ["SimpleTest", "ok"];
-    for each (var import in imports) {
-      window[import] = window.opener.wrappedJSObject[import];
+    for each (var name in imports) {
+      window[name] = window.opener.wrappedJSObject[name];
     }
 
     function finish() {
diff --git a/toolkit/content/tests/chrome/bug331215_window.xul b/toolkit/content/tests/chrome/bug331215_window.xul
index ea755c2aaca1..914c73ec1b3f 100644
--- a/toolkit/content/tests/chrome/bug331215_window.xul
+++ b/toolkit/content/tests/chrome/bug331215_window.xul
@@ -55,8 +55,8 @@
     var gBrowser;
 
     var imports = ["SimpleTest", "ok"];
-    for each (var import in imports) {
-      window[import] = window.opener.wrappedJSObject[import];
+    for each (var name in imports) {
+      window[name] = window.opener.wrappedJSObject[name];
     }
 
     function finish() {
diff --git a/toolkit/content/tests/chrome/bug451286_window.xul b/toolkit/content/tests/chrome/bug451286_window.xul
index 505b1fa0f28d..535aeb2ff96a 100644
--- a/toolkit/content/tests/chrome/bug451286_window.xul
+++ b/toolkit/content/tests/chrome/bug451286_window.xul
@@ -57,8 +57,8 @@
     var gBrowser;
 
     var imports = ["SimpleTest", "ok", "snapshotWindow", "compareSnapshots"];
-    for each (var import in imports) {
-      window[import] = window.opener.wrappedJSObject[import];
+    for each (var name in imports) {
+      window[name] = window.opener.wrappedJSObject[name];
     }
 
     function finish() {
diff --git a/toolkit/content/tests/chrome/bug451540_window.xul b/toolkit/content/tests/chrome/bug451540_window.xul
index 6a0c127d0366..3254db7967b0 100644
--- a/toolkit/content/tests/chrome/bug451540_window.xul
+++ b/toolkit/content/tests/chrome/bug451540_window.xul
@@ -62,8 +62,8 @@
     }
 
     var imports = [ "SimpleTest", "ok"];
-      for each (var import in imports) {
-        window[import] = window.opener.wrappedJSObject[import];
+      for each (var name in imports) {
+        window[name] = window.opener.wrappedJSObject[name];
       }