To release a server from load by controlling maintenance of a shopping cart from a client station.

A browser of a client station sends the shopping page request to a server, and the server responds to the request and sends the shopping page file storing the item capable of being selected by using a browser by a user to the browser. The browser generates the additional request to store the selected item and sends it to the server. The server receives the additional request and initialize the shopping cart list. The server adds the selected item to the shopping cart list 178, converts the list into the cart field 180, generates the new shopping page file, implants the cart field into the new shopping page file 182 and sends the new shopping page file to the browser 183.