diff --git a/dom/base/nsDOMClassInfo.cpp b/dom/base/nsDOMClassInfo.cpp
index d42fbb9966c..6a4ca73ee7c 100644
--- a/dom/base/nsDOMClassInfo.cpp
+++ b/dom/base/nsDOMClassInfo.cpp
@@ -10516,15 +10516,15 @@ nsStorage2SH::GetProperty(nsIXPConnectWrappedNative *wrapper, JSContext *cx,
   JSAutoRequest ar(cx);
 
   if (DOMStringIsNull(val)) {
-      *vp = JSVAL_NULL;
-  }
-  else {
-      JSString *str =
-        ::JS_NewUCStringCopyN(cx, reinterpret_cast<const jschar *>(val.get()),
-                              val.Length());
-      NS_ENSURE_TRUE(str, NS_ERROR_OUT_OF_MEMORY);
+    // No such key.
+    *vp = JSVAL_VOID;
+  } else {
+    JSString* str =
+      JS_NewUCStringCopyN(cx, static_cast<const jschar *>(val.get()),
+                          val.Length());
+    NS_ENSURE_TRUE(str, NS_ERROR_OUT_OF_MEMORY);
 
-      *vp = STRING_TO_JSVAL(str);
+    *vp = STRING_TO_JSVAL(str);
   }
 
   return NS_SUCCESS_I_DID_SOMETHING;
diff --git a/dom/tests/mochitest/localstorage/test_localStorageBase.html b/dom/tests/mochitest/localstorage/test_localStorageBase.html
index f9d0d231cc5..ed8ffc57a00 100644
--- a/dom/tests/mochitest/localstorage/test_localStorageBase.html
+++ b/dom/tests/mochitest/localstorage/test_localStorageBase.html
@@ -17,16 +17,16 @@ function startTest()
   is(localStorage.key(-1), null, "key() should return null for out-of-bounds access");
   is(localStorage.key(1), null, "key() should return null for out-of-bounds access");
   is(localStorage.getItem("nonexisting"), null, "Nonexisting item is null (getItem())");
-  is(localStorage["nonexisting"], null, "Nonexisting item is null (array access)");
-  is(localStorage.nonexisting, null, "Nonexisting item is null (property access)");
+  is(localStorage["nonexisting"], undefined, "Nonexisting item is undefined (array access)");
+  is(localStorage.nonexisting, undefined, "Nonexisting item is undefined (property access)");
   localStorage.removeItem("nonexisting"); // Just check there is no exception
 
   is(typeof localStorage.getItem("nonexisting"), "object", "getItem('nonexisting') is object");
-  is(typeof localStorage["nonexisting"], "object", "['nonexisting'] is object");
-  is(typeof localStorage.nonexisting, "object", "nonexisting is object");
+  is(typeof localStorage["nonexisting"], "undefined", "['nonexisting'] is undefined");
+  is(typeof localStorage.nonexisting, "undefined", "nonexisting is undefined");
   is(typeof localStorage.getItem("nonexisting2"), "object", "getItem('nonexisting2') is object");
-  is(typeof localStorage["nonexisting2"], "object", "['nonexisting2'] is object");
-  is(typeof localStorage.nonexisting2, "object", "nonexisting2 is object");
+  is(typeof localStorage["nonexisting2"], "undefined", "['nonexisting2'] is undefined");
+  is(typeof localStorage.nonexisting2, "undefined", "nonexisting2 is undefined");
 
   var mozStorageChangedReceived = 0;
   var localStorageCopy = localStorage;
@@ -50,11 +50,11 @@ function startTest()
   localStorage.removeItem("empty");
   is(localStorage.length, 0, "The storage has no keys");
   is(localStorage.getItem("empty"), null, "empty item is null (getItem())");
-  is(localStorage["empty"], null, "empty item is null (array access)");
-  is(localStorage.empty, null, "empty item is null (property access)");
+  is(localStorage["empty"], undefined, "empty item is undefined (array access)");
+  is(localStorage.empty, undefined, "empty item is undefined (property access)");
   is(typeof localStorage.getItem("empty"), "object", "getItem('empty') is object");
-  is(typeof localStorage["empty"], "object", "['empty'] is object");
-  is(typeof localStorage.empty, "object", "empty is object");
+  is(typeof localStorage["empty"], "undefined", "['empty'] is undefined");
+  is(typeof localStorage.empty, "undefined", "empty is undefined");
 
   // add one key, check it is there
   localStorage.setItem("key1", "value1");
@@ -80,8 +80,8 @@ function startTest()
   is(localStorage.getItem("key1"), null, "\'key1\' removed");
 
   is(typeof localStorage.getItem("key1"), "object", "getItem('key1') is object");
-  is(typeof localStorage["key1"], "object", "['key1'] is object");
-  is(typeof localStorage.key1, "object", "key1 is object");
+  is(typeof localStorage["key1"], "undefined", "['key1'] is object");
+  is(typeof localStorage.key1, "undefined", "key1 is object");
 
   // add one key, check it is there
   localStorage.setItem("key1", "value1");
diff --git a/dom/tests/mochitest/localstorage/test_localStorageBasePrivateBrowsing.html b/dom/tests/mochitest/localstorage/test_localStorageBasePrivateBrowsing.html
index 3afaabd76ff..42e7bc5cafd 100644
--- a/dom/tests/mochitest/localstorage/test_localStorageBasePrivateBrowsing.html
+++ b/dom/tests/mochitest/localstorage/test_localStorageBasePrivateBrowsing.html
@@ -34,16 +34,16 @@ function doTest()
   is(localStorage.key(-1), null, "key() should return null for out-of-bounds access");
   is(localStorage.key(1), null, "key() should return null for out-of-bounds access");
   is(localStorage.getItem("nonexisting"), null, "Nonexisting item is null (getItem())");
-  is(localStorage["nonexisting"], null, "Nonexisting item is null (array access)");
-  is(localStorage.nonexisting, null, "Nonexisting item is null (property access)");
+  is(localStorage["nonexisting"], undefined, "Nonexisting item is null (array access)");
+  is(localStorage.nonexisting, undefined, "Nonexisting item is null (property access)");
   localStorage.removeItem("nonexisting"); // Just check there is no exception
 
   is(typeof localStorage.getItem("nonexisting"), "object", "getItem('nonexisting') is object");
-  is(typeof localStorage["nonexisting"], "object", "['nonexisting'] is object");
-  is(typeof localStorage.nonexisting, "object", "nonexisting is object");
+  is(typeof localStorage["nonexisting"], "undefined", "['nonexisting'] is undefined");
+  is(typeof localStorage.nonexisting, "undefined", "nonexisting is undefined");
   is(typeof localStorage.getItem("nonexisting2"), "object", "getItem('nonexisting2') is object");
-  is(typeof localStorage["nonexisting2"], "object", "['nonexisting2'] is object");
-  is(typeof localStorage.nonexisting2, "object", "nonexisting2 is object");
+  is(typeof localStorage["nonexisting2"], "undefined", "['nonexisting2'] is undefined");
+  is(typeof localStorage.nonexisting2, "undefined", "nonexisting2 is undefined");
 
   // add an empty-value key
   localStorage.setItem("empty", "");
@@ -56,11 +56,11 @@ function doTest()
   localStorage.removeItem("empty");
   is(localStorage.length, 0, "The storage has no keys");
   is(localStorage.getItem("empty"), null, "empty item is null (getItem())");
-  is(localStorage["empty"], null, "empty item is null (array access)");
-  is(localStorage.empty, null, "empty item is null (property access)");
+  is(localStorage["empty"], null, "empty item is undefined (array access)");
+  is(localStorage.empty, null, "empty item is undefined (property access)");
   is(typeof localStorage.getItem("empty"), "object", "getItem('empty') is object");
-  is(typeof localStorage["empty"], "object", "['empty'] is object");
-  is(typeof localStorage.empty, "object", "empty is object");
+  is(typeof localStorage["empty"], "undefined", "['empty'] is undefined");
+  is(typeof localStorage.empty, "undefined", "empty is undefined");
 
   // add one key, check it is there
   localStorage.setItem("key1", "value1");
@@ -86,8 +86,8 @@ function doTest()
   is(localStorage.getItem("key1"), null, "\'key1\' removed");
 
   is(typeof localStorage.getItem("key1"), "object", "getItem('key1') is object");
-  is(typeof localStorage["key1"], "object", "['key1'] is object");
-  is(typeof localStorage.key1, "object", "key1 is object");
+  is(typeof localStorage["key1"], "undefined", "['key1'] is undefined");
+  is(typeof localStorage.key1, "undefined", "key1 is undefined");
 
   // add one key, check it is there
   localStorage.setItem("key1", "value1");
diff --git a/dom/tests/mochitest/localstorage/test_localStorageBaseSessionOnly.html b/dom/tests/mochitest/localstorage/test_localStorageBaseSessionOnly.html
index 44a2937a9b6..f3c803e6052 100644
--- a/dom/tests/mochitest/localstorage/test_localStorageBaseSessionOnly.html
+++ b/dom/tests/mochitest/localstorage/test_localStorageBaseSessionOnly.html
@@ -25,16 +25,16 @@ function startTest()
   is(localStorage.key(-1), null, "key() should return null for out-of-bounds access");
   is(localStorage.key(1), null, "key() should return null for out-of-bounds access");
   is(localStorage.getItem("nonexisting"), null, "Nonexisting item is null (getItem())");
-  is(localStorage["nonexisting"], null, "Nonexisting item is null (array access)");
-  is(localStorage.nonexisting, null, "Nonexisting item is null (property access)");
+  is(localStorage["nonexisting"], undefined, "Nonexisting item is undefined (array access)");
+  is(localStorage.nonexisting, undefined, "Nonexisting item is undefined (property access)");
   localStorage.removeItem("nonexisting"); // Just check there is no exception
 
   is(typeof localStorage.getItem("nonexisting"), "object", "getItem('nonexisting') is object");
-  is(typeof localStorage["nonexisting"], "object", "['nonexisting'] is object");
-  is(typeof localStorage.nonexisting, "object", "nonexisting is object");
+  is(typeof localStorage["nonexisting"], "undefined", "['nonexisting'] is undefined");
+  is(typeof localStorage.nonexisting, "undefined", "nonexisting is undefined");
   is(typeof localStorage.getItem("nonexisting2"), "object", "getItem('nonexisting2') is object");
-  is(typeof localStorage["nonexisting2"], "object", "['nonexisting2'] is object");
-  is(typeof localStorage.nonexisting2, "object", "nonexisting2 is object");
+  is(typeof localStorage["nonexisting2"], "undefined", "['nonexisting2'] is undefined");
+  is(typeof localStorage.nonexisting2, "undefined", "nonexisting2 is undefined");
 
   // add an empty-value key
   localStorage.setItem("empty", "");
@@ -47,11 +47,11 @@ function startTest()
   localStorage.removeItem("empty");
   is(localStorage.length, 0, "The storage has no keys");
   is(localStorage.getItem("empty"), null, "empty item is null (getItem())");
-  is(localStorage["empty"], null, "empty item is null (array access)");
-  is(localStorage.empty, null, "empty item is null (property access)");
+  is(localStorage["empty"], undefined, "empty item is undefined (array access)");
+  is(localStorage.empty, undefined, "empty item is undefined (property access)");
   is(typeof localStorage.getItem("empty"), "object", "getItem('empty') is object");
-  is(typeof localStorage["empty"], "object", "['empty'] is object");
-  is(typeof localStorage.empty, "object", "empty is object");
+  is(typeof localStorage["empty"], "undefined", "['empty'] is undefined");
+  is(typeof localStorage.empty, "undefined", "empty is undefined");
 
   // add one key, check it is there
   localStorage.setItem("key1", "value1");
@@ -77,8 +77,8 @@ function startTest()
   is(localStorage.getItem("key1"), null, "\'key1\' removed");
 
   is(typeof localStorage.getItem("key1"), "object", "getItem('key1') is object");
-  is(typeof localStorage["key1"], "object", "['key1'] is object");
-  is(typeof localStorage.key1, "object", "key1 is object");
+  is(typeof localStorage["key1"], "undefined", "['key1'] is undefined");
+  is(typeof localStorage.key1, "undefined", "key1 is undefined");
 
   // add one key, check it is there
   localStorage.setItem("key1", "value1");
diff --git a/dom/tests/mochitest/sessionstorage/test_sessionStorageBase.html b/dom/tests/mochitest/sessionstorage/test_sessionStorageBase.html
index 8fd29e269f2..e23aba011e9 100644
--- a/dom/tests/mochitest/sessionstorage/test_sessionStorageBase.html
+++ b/dom/tests/mochitest/sessionstorage/test_sessionStorageBase.html
@@ -22,16 +22,16 @@ function startTest()
   is(sessionStorage.key(-1), null, "key() should return null for out-of-bounds access");
   is(sessionStorage.key(1), null, "key() should return null for out-of-bounds access");
   is(sessionStorage.getItem("nonexisting"), null, "Nonexisting item is null (getItem())");
-  is(sessionStorage["nonexisting"], null, "Nonexisting item is null (array access)");
-  is(sessionStorage.nonexisting, null, "Nonexisting item is null (property access)");
+  is(sessionStorage["nonexisting"], undefined, "Nonexisting item is undefined (array access)");
+  is(sessionStorage.nonexisting, undefined, "Nonexisting item is undefined (property access)");
   sessionStorage.removeItem("nonexisting"); // Just check there is no exception
 
   is(typeof sessionStorage.getItem("nonexisting"), "object", "getItem('nonexisting') is object");
-  is(typeof sessionStorage["nonexisting"], "object", "['nonexisting'] is object");
-  is(typeof sessionStorage.nonexisting, "object", "nonexisting is object");
+  is(typeof sessionStorage["nonexisting"], "undefined", "['nonexisting'] is undefined");
+  is(typeof sessionStorage.nonexisting, "undefined", "nonexisting is undefined");
   is(typeof sessionStorage.getItem("nonexisting2"), "object", "getItem('nonexisting2') is object");
-  is(typeof sessionStorage["nonexisting2"], "object", "['nonexisting2'] is object");
-  is(typeof sessionStorage.nonexisting2, "object", "nonexisting2 is object");
+  is(typeof sessionStorage["nonexisting2"], "undefined", "['nonexisting2'] is undefined");
+  is(typeof sessionStorage.nonexisting2, "undefined", "nonexisting2 is undefined");
 
   var mozStorageChangedReceived = 0;
   var sessionStorageCopy = sessionStorage;
@@ -55,11 +55,11 @@ function startTest()
   sessionStorage.removeItem("empty");
   is(sessionStorage.length, 0, "The storage has no keys");
   is(sessionStorage.getItem("empty"), null, "empty item is null (getItem())");
-  is(sessionStorage["empty"], null, "empty item is null (array access)");
-  is(sessionStorage.empty, null, "empty item is null (property access)");
+  is(sessionStorage["empty"], undefined, "empty item is undefined (array access)");
+  is(sessionStorage.empty, undefined, "empty item is undefined (property access)");
   is(typeof sessionStorage.getItem("empty"), "object", "getItem('empty') is object");
-  is(typeof sessionStorage["empty"], "object", "['empty'] is object");
-  is(typeof sessionStorage.empty, "object", "empty is object");
+  is(typeof sessionStorage["empty"], "undefined", "['empty'] is undefined");
+  is(typeof sessionStorage.empty, "undefined", "empty is undefined");
 
   // add one key, check it is there
   sessionStorage.setItem("key1", "value1");
@@ -85,8 +85,8 @@ function startTest()
   is(sessionStorage.getItem("key1"), null, "\'key1\' removed");
 
   is(typeof sessionStorage.getItem("key1"), "object", "getItem('key1') is object");
-  is(typeof sessionStorage["key1"], "object", "['key1'] is object");
-  is(typeof sessionStorage.key1, "object", "key1 is object");
+  is(typeof sessionStorage["key1"], "undefined", "['key1'] is undefined");
+  is(typeof sessionStorage.key1, "undefined", "key1 is undefined");
 
   // add one key, check it is there
   sessionStorage.setItem("key1", "value1");