diff --git a/coffee/pygal-tooltips.coffee b/coffee/pygal-tooltips.coffee
index d0761ce..5895e33 100644
--- a/coffee/pygal-tooltips.coffee
+++ b/coffee/pygal-tooltips.coffee
@@ -13,7 +13,7 @@ addClass = (elt, cls) ->
 
 removeClass = (elt, cls) ->
   if elt.classList
-    elt.classList.remove className
+    elt.classList.remove cls.className
   else
     elt.className.baseVal = elt.className.baseVal.replace(
       new RegExp(