A distributed application consisting of a server portion (back end), where most of the processing and storage is performed, and a client portion (front end) that provides a user interface.
In the client/server model, an application is split into a front-end client component and a back-end server component. The front-end client part of the application runs on a workstation and receives data that is input by the user. The client component prepares the data for the server by preprocessing it in some fashion, and then sends the processed information to the server, usually in the form of a request for some service. The back-end server component receives the client's request, processes it, and returns information to the client. The client receives the information returned from the server and presents it to the user by way of its user interface.
An example of a client/server application is a Web application that is designed for Internet Information Services (IIS) using a combination of server-side Active Server Pages (ASP) programming and client-side scripting. The ASP scripts run on the Web server, while the client-side scripts run on the client Web browser.