diff --git a/src/xhr.js b/src/xhr.js
index f66bb8b..0497c6d 100644
--- a/src/xhr.js
+++ b/src/xhr.js
@@ -11,7 +11,7 @@ HTMLImports.addModule(function(scope) {
 /*
   xhr processor.
 */
-xhr = {
+var xhr = {
   async: true,
 
   ok: function(request) {