do not raise error if there is no gadgets on the page

renderjs.js

@@ -549,7 +549,12 @@ $(document).ready(function () {
         RenderJs.bootstrap($('body'));
     }
     if (RENDERJS_ENABLE_IMPLICIT_INTERACTION_BIND) {
-      RenderJs.GadgetIndex.getRootGadget().getDom().bind("ready",
+      var root_gadget = RenderJs.GadgetIndex.getRootGadget();
+      // We might have a page without gadgets.
+      // Be careful, right now we can be in this case because
+      // asynchronous gadget loading is not finished
+      if (root_gadget !== undefined) {
+        root_gadget.getDom().bind("ready",
           function () {
             // examine all Intaction Gadgets and bind accordingly
             $("div[data-gadget-connection]").each( function(index, element) {
@@ -558,4 +563,5 @@ $(document).ready(function () {
           }
         );
       }
+    }
 });