Hi
I founded a solution to do this.
There are three modules
1.An application at client system to access the serial port
2.An application which runs on a server providing an interface between the application and web page controls
3.A web interface which provides a way of interacting with client application
For designing the application to access the serial port at client ,I opted for c#.Net
For developing an application which provides interface between clients , I used the concept of web services
For developing an interactive web interface, I used ASP.Net (Active Server Pages)