WEB应用程序无状态，无法主动更新客户端的显示。需要一种定时更新机制，来保持与服务器的同步。 可以使用ASP.NET Ajax中的Timer控件来实现-WEB application stateless, unable to take the initiative to update the client' s display. Need for a regular update mechanism to maintain synchronization with the server

ajax无刷新技术应用，包括updatepanel控件、UpdateProgress控件和Timer控件，以及AJAX Control Tookit(Ajax no refresh technology applications, including UpdatePanel controls, UpdateProgress controls and Timer controls, as well as AJAX Control Tookit)

进度栏的应用,用timer()组件来控制时间,进度栏模拟活动的进度()