Object.isAncestorOf

Object.isAncestorOf = function isAncestorOf(parent,child) {
   if (child===null || child===undefined) return false;
   if (parent === null) return true;
   child = Object(child);
   var proto = Object.getPrototypeOf(child);
   if (proto === parent) return true;
   return isAncestorOf(parent,proto);
}