diff --git a/common/static/js/capa/jsinput.js b/common/static/js/capa/jsinput.js
index 6b7cac2429..0137d4ca7b 100644
--- a/common/static/js/capa/jsinput.js
+++ b/common/static/js/capa/jsinput.js
@@ -24,7 +24,11 @@
         oldthis.pop();
         oldthis = oldthis.join();
         var newthis = _deepKey(obj, oldthis);
-        return func.apply(newthis);
+
+        var args = Array.prototype.slice.call(arguments);
+        args = args.slice(2, args.length);
+
+        return func.apply(newthis, args);
     };
    
     // First time this function was called?