1. A method for adding functionality to a web-page served by a first web-server, the method comprising: at a second web-server, receiving a request from a client-computer for code to add purchase functionality to the web-page; sending the code to the client-computer; receiving a request from the client-computer containing information about objects identified in the web-page as relating to the purchase functionality and a request for information about the objects; sending information about the objects to the client-computer; receiving an instruction to complete the purchase from the client-computer; and sending a confirmation of the completion of the purchase to the client-computer.