this element by class name binding

static/nb.js

@@ -130,7 +130,7 @@ function nbInit(a,b){
                                 arguments.callee(classSubnodes[i], $s, selector, value[key]); // recursively fill subnode with that data. No reason to pass a key, because key are class selector, not value for option
                             }
                             if (item.classList.contains(key)){
-                                arguments.callee(item, $s, selector, value[key], null, true); // recursively fill subnode with that data. No reason to pass a key, because key are class selector, not value for option
+                                arguments.callee(item, $s, selector, value[key], undefined, true); // recursively fill subnode with that data. No reason to pass a key, because key are class selector, not value for option
                             }
                         }
                         return;