JavaScript 日期getTimezoneOffset方法

<html>
   <head>
      <title>JavaScript getTimezoneOffset Method</title>
   </head>

   <body>

      <script type = "text/javascript">
         var dt = new Date();
         var tz = dt.getTimezoneOffset();
         document.write("getTimezoneOffset() : " + tz );
      </script>

   </body>
</html>