diff --git a/lib/ace/keyboard/state_handler.js b/lib/ace/keyboard/state_handler.js
index f0c2face..15d17c8c 100644
--- a/lib/ace/keyboard/state_handler.js
+++ b/lib/ace/keyboard/state_handler.js
@@ -52,7 +52,7 @@ StateHandler.prototype = {
      * need to be adapted.
      */
     $buildKeymappingRegex: function(keymapping) {
-        for (state in keymapping) {
+        for (var state in keymapping) {
             this.$buildBindingsRegex(keymapping[state]);
         }
         return keymapping;