diff --git a/index.html b/index.html
index 1692855..4f8fdb0 100644
--- a/index.html
+++ b/index.html
@@ -39,7 +39,7 @@
 
     window.phet.chipper.stringPath = '../';
     phet.chipper.locale = 'en';
-    phet.chipper.loadModules = () => {};
+    phet.chipper.loadModules = function() {};
 
   </script>