Jscript.net可以用JScript 或任意NET 框架語言(如 C #,VB7.0) 通過增加extends主題詞在類聲明以后來繼承和擴展現有類。這能力允許Jscript.net非常容易地利用 NET 平臺的豐厚資源。為了說明這些,給出一個程序。這個程序擴展了NET 框架的ServiceBase 類。
// 導入需要的.net命名空間
import System;
import System.ServiceProcess;
import System.Diagnostics;
import System.Timers;
class SimpleService extends ServiceBase
{
   private var timer : Timer;
   function SimpleService()
   {
      CanPauseAndContinue = true;
      ServiceName = "JScript Service";
      timer = new Timer();
      timer.Interval = 1000;
      timer.AddOnTimer(OnTimer);
   }
   protected override function OnStart(args : String[])
   {
      EventLog.WriteEntry("JScript Service started");
      timer.Enabled = true;
   }
   protected override function OnStop()
   {
      EventLog.WriteEntry("JScript Service stopped");
      timer.Enabled = false;
   }
   protected override function OnPause()
   {
      EventLog.WriteEntry("JScript Service paused");
      timer.Enabled = false;
   }
   protected override function OnContinue()
   {
      EventLog.WriteEntry("JScript Service continued");
      timer.Enabled = true;
   }
   function OnTimer(source : Object, e : EventArgs)
   {
      EventLog.WriteEntry("Hello World from JScript!");
   }
}
ServiceBase.Run(new SimpleService());