diff --git a/twake/frontend/public/index.html b/twake/frontend/public/index.html
index 26abfc705..9ad1ae131 100644
--- a/twake/frontend/public/index.html
+++ b/twake/frontend/public/index.html
@@ -143,6 +143,7 @@
         const canaryTag = document.createElement("div");
         canaryTag.id = "canary_tag";
         document.body.appendChild(canaryTag);
+        window.canary = true;
       }
     </script>
   </body>