--- a/dom/base/nsLocation.cpp
+++ b/dom/base/nsLocation.cpp
@@ -32,16 +32,17 @@
 #include "nsDOMError.h"
 #include "nsDOMClassInfoID.h"
 #include "nsCRT.h"
 #include "nsIProtocolHandler.h"
 #include "nsReadableUtils.h"
 #include "nsITextToSubURI.h"
 #include "nsJSUtils.h"
 #include "jsfriendapi.h"
+#include "nsContentUtils.h"
 
 static nsresult
 GetContextFromStack(nsIJSContextStack *aStack, JSContext **aContext)
 {
   nsCOMPtr<nsIJSContextStackIterator>
     iterator(do_CreateInstance("@mozilla.org/js/xpc/ContextStackIterator;1"));
   NS_ENSURE_TRUE(iterator, NS_ERROR_FAILURE);
 
@@ -163,28 +164,34 @@ GetFrameDocument(JSContext *cx, JSStackF
   nsCOMPtr<nsIDocument> doc = do_QueryInterface(domDoc);
   return doc.forget();
 }
 
 nsresult
 nsLocation::CheckURL(nsIURI* aURI, nsIDocShellLoadInfo** aLoadInfo)
 {
   *aLoadInfo = nsnull;
+  JSContext* cx;
+  if ((cx = nsContentUtils::GetCurrentJSContext())) {
+    nsIScriptSecurityManager* ssm = nsContentUtils::GetSecurityManager();
+    NS_ENSURE_STATE(ssm);
+    // Check to see if URI is allowed.
+    nsresult rv = ssm->CheckLoadURIFromScript(cx, aURI);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
 
   nsCOMPtr<nsIDocShell> docShell(do_QueryReferent(mDocShell));
   NS_ENSURE_TRUE(docShell, NS_ERROR_NOT_AVAILABLE);
 
   nsresult rv;
   // Get JSContext from stack.
   nsCOMPtr<nsIJSContextStack>
     stack(do_GetService("@mozilla.org/js/xpc/ContextStack;1", &rv));
   NS_ENSURE_SUCCESS(rv, rv);
 
-  JSContext *cx;
-
   NS_ENSURE_SUCCESS(GetContextFromStack(stack, &cx), NS_ERROR_FAILURE);
 
   nsCOMPtr<nsISupports> owner;
   nsCOMPtr<nsIURI> sourceURI;
 
   if (cx) {
     // No cx means that there's no JS running, or at least no JS that
     // was run through code that properly pushed a context onto the