diff --git a/prototype/UI/index.html b/prototype/UI/index.html
index 8993f266e..d9b2229ff 100644
--- a/prototype/UI/index.html
+++ b/prototype/UI/index.html
@@ -224,9 +224,9 @@
     }
 
     function Syntax(json, continuation) {
-        if (json instanceof Array) { this.indexed = json.map(continuation); }
-        else if (json instanceof Object) { this.keyed = (new Dictionary(json)).map(continuation); }
-        else this.leaf = json;
+        if (json.indexed != null) { this.indexed = json.map(continuation); }
+        if (json.keyed != null) { this.keyed = (new Dictionary(json)).map(continuation); }
+        if (json.leaf != null) { this.leaf = json; }
         return this;
     }