1. A method for adding functionality to a web-page served to a client-computer by a first web-server, the method comprising: at a second web-server including a microprocessor, receiving a first request from the client-computer for client-side script source code to add purchase functionality to the web-page being served by the first web-server; sending the client-side script source code for purchase functionality to the client-computer using the microprocessor, wherein said client-side script source code for purchase functionality includes instructions that cause the client-computer to insert a script element into the web-page; receiving a second request for client-side script source code from the client-computer, the second request including a URL with information about objects identified in the web-page as relating to the purchase functionality and a request for information about the objects; generating client-side script source code, based on the second request, including information about the objects encoded using a scripting language; sending the client-side script source code including the information about the objects to the client-computer using the microprocessor; receiving a third request for client-side script source code from the client computer, the third request including a URL with instruction to complete the purchase from the client-computer and payment information; and sending client-side script source code including a confirmation of the completion of the purchase encoded using the scripting language to the client-computer and instructions to cause the client-computer to display the confirmation using the microprocessor.