diff --git a/public/javascripts/embed.js b/public/javascripts/embed.js
index 4412a33c117..16f7e05f270 100644
--- a/public/javascripts/embed.js
+++ b/public/javascripts/embed.js
@@ -64,7 +64,7 @@
   }
 
   function normalizeUrl(url) {
-    return url.replace(/^https?(\:\/\/)?/, '');
+    return url.toLowerCase().replace(/^https?(\:\/\/)?/, '');
   }
 
   function postMessageReceived(e) {