1. A method for executing an RPC (Remote Procedure Call) over HTTP from a Web page within the application window at a client device, the method comprising: containing, in the application window of a client device, at least one Web page; transmitting, to a server, an HTTP request initiated by a first HTML element; invoking, at a server, a procedure or a set of program code identified by the URL of said first HTML element; receiving, at said Web browser from said server in the transmitting action, output of said procedure or program code in the invoking action into a second HTML <script> element.