The present subject matter relates generally to systems and methods for adding interactive functionality to a website, other digital media objects, and computer processor applications. Systems and methods for adding functionality to content served by a first server, may include receiving, at a second server, a request from a client-computer for code to add purchase functionality to the content. The code may be sent to the client-computer based on the request. A further request may be received from the client-computer containing information about objects identified in the content as relating to the purchase functionality and a request for information about the objects. Information about the objects may be sent to the client-computer based on the further request. An instruction to complete the purchase may be received from the client-computer, and a confirmation of the completion of the purchase may be sent to the client-computer. The content may be an HTML document and the objects may be objects according to the HTML Document Object Model.