在服务器上推送新的构建之后刷新客户端浏览器窗口

We are using ExtJs 4.1 along with ASP.NET MVC. We release some updates or features after every 2-3 weeks. Most of the users don't close their browsers windows and hence use the old JavaScript. What options we have to forcefully refreshed client browser window.We are using ExtJs 4.1 along with ASP.NET MVC.