1. A method for implementing a model-view-controller (MVC) Web application comprising: establishing a session for the MVC Web application between a Web server of a Web domain and a browser of a client of a local domain, wherein the MVC Web application is constructed so that view and controller functionality are provided by components executing in the Web domain and where model functionality is provided by components executing in the local domain; during the session, serving an expeditor runtime component from the Web domain to the local domain for the MVC Web application session which provides the model functions for the MVC Web application, wherein a running instance of the expeditor runtime component is referred to as the expeditor runtime and wherein the expeditor runtime is an extension to the browser; during the session, serving at least one widget from the Web domain to the local domain, wherein the widget is downloaded from the Web server of the Web domain, and wherein an instance of the expeditor runtime executes code of the widget for processing of the end-user data; wherein a bridge is configured to allow the remotely rendered MVC Web application to access local resources of the local domain without exposing end-user data of the local domain to the Web domain; and conducting the session, wherein model functions of the expeditor runtime running in the local domain handle processing of the end-user data.