Obtenha o ano local em JS

<html>
   <head>
      <title>JavaScript getFullYear Method</title>
   </head>
   <body>
      <script>
         var dt = new Date("December 30, 2017 21:25:10");
         document.write("getFullYear() : " + dt.getFullYear() );
      </script>
   </body>
</html>
Dineth S