diff --git a/lib/jquery.raty.js b/lib/jquery.raty.js
index <HASH>..<HASH> 100644
--- a/lib/jquery.raty.js
+++ b/lib/jquery.raty.js
@@ -194,7 +194,7 @@
         }
       });
     }, _callback: function(options) {
-      for (i in options) {
+      for (var i in options) {
         if (typeof this.opt[options[i]] === 'function') {
           this.opt[options[i]] = this.opt[options[i]].call(this);
         }
fixing usage of undefined variable in _callback function