1 files changed, 2 insertions, 0 deletions
diff --git a/web-ui/app/js/sandbox.js b/web-ui/app/js/sandbox.js
index f9e708d6..33b16ea4 100644
--- a/web-ui/app/js/sandbox.js
+++ b/web-ui/app/js/sandbox.js
@@ -4,6 +4,8 @@
   window.onmessage = function (e) {
     if (e.data.html) {
       document.body.innerHTML = e.data.html;
+      var mainWindow = e.source;
+      mainWindow.postMessage('data ok', e.origin);
     }
   };
 })();