diff --git a/static/index.html b/static/index.html
index b7085458b..1cc71bd9b 100644
--- a/static/index.html
+++ b/static/index.html
@@ -125,6 +125,6 @@
             }
             
             //start the costum js
-            if(costumStart) costumStart();
+            if(typeof costumStart == "function") costumStart();
         </script>
 </html>
diff --git a/static/js/pad2.js b/static/js/pad2.js
index aa1f7ccd7..f442607d7 100644
--- a/static/js/pad2.js
+++ b/static/js/pad2.js
@@ -30,7 +30,7 @@ $(document).ready(function()
   }
 
   //start the costum js
-  if(costumStart) costumStart();
+  if(typeof costumStart == "function") costumStart();
 
   handshake();
 });
diff --git a/static/timeslider.html b/static/timeslider.html
index fbcbc149e..110b6d128 100644
--- a/static/timeslider.html
+++ b/static/timeslider.html
@@ -58,7 +58,7 @@
   $(document).ready(function () 
   {
     //start the costum js
-    if(costumStart) costumStart();
+    if(typeof costumStart == "function") costumStart();
     
     //get the padId out of the url 
     var urlParts= document.location.pathname.split("/");