diff --git a/js/.jshintrc b/js/.jshintrc
index d899270..e4afdcf 100644
--- a/js/.jshintrc
+++ b/js/.jshintrc
@@ -7,6 +7,8 @@
   "eqeqeq"    : true,
   "eqnull"    : true,
   "expr"      : true,
+  "forin"     : true,
+  "freeze"    : true,
   "indent"    : 2,
   "laxbreak"  : true,
   "nonbsp"    : true,
diff --git a/js/push.js b/js/push.js
index ac3b4fa..30b5c99 100644
--- a/js/push.js
+++ b/js/push.js
@@ -177,11 +177,13 @@
     if (transitionFromObj.transition) {
       activeObj = extendWithDom(activeObj, '.content', activeDom.cloneNode(true));
       for (key in bars) {
-        barElement = document.querySelector(bars[key]);
-        if (activeObj[key]) {
-          swapContent(activeObj[key], barElement);
-        } else if (barElement) {
-          barElement.parentNode.removeChild(barElement);
+        if (bars.hasOwnProperty(key)) {
+          barElement = document.querySelector(bars[key]);
+          if (activeObj[key]) {
+            swapContent(activeObj[key], barElement);
+          } else if (barElement) {
+            barElement.parentNode.removeChild(barElement);
+          }
         }
       }
     }
@@ -208,7 +210,9 @@
     options.container = options.container || options.transition ? document.querySelector('.content') : document.body;
 
     for (key in bars) {
-      options[key] = options[key] || document.querySelector(bars[key]);
+      if (bars.hasOwnProperty(key)) {
+        options[key] = options[key] || document.querySelector(bars[key]);
+      }
     }
 
     if (xhr && xhr.readyState < 4) {
@@ -269,11 +273,13 @@
 
     if (options.transition) {
       for (key in bars) {
-        barElement = document.querySelector(bars[key]);
-        if (data[key]) {
-          swapContent(data[key], barElement);
-        } else if (barElement) {
-          barElement.parentNode.removeChild(barElement);
+        if (bars.hasOwnProperty(key)) {
+          barElement = document.querySelector(bars[key]);
+          if (data[key]) {
+            swapContent(data[key], barElement);
+          } else if (barElement) {
+            barElement.parentNode.removeChild(barElement);
+          }
         }
       }
     }
@@ -408,7 +414,9 @@
     var result = {};
 
     for (i in obj) {
-      result[i] = obj[i];
+      if (obj.hasOwnProperty(i)) {
+        result[i] = obj[i];
+      }
     }
 
     Object.keys(bars).forEach(function (key) {