diff --git a/assets/javascripts/views/content/content.coffee b/assets/javascripts/views/content/content.coffee
index 4a67be82..e6c7cbff 100644
--- a/assets/javascripts/views/content/content.coffee
+++ b/assets/javascripts/views/content/content.coffee
@@ -154,4 +154,4 @@ class app.views.Content extends app.View
     try $.id decodeURIComponent(hash) catch
 
   isExternalUrl: (url) ->
-    url?[0..4] in ['http:', 'https:']
+    url?[0..5] in ['http:/', 'https:']