A system for storing a session cookie from another client application program, in which a separate client application is allowed to launch an external browser, and to supply a browser with a session cookie containing user specific session information. The browser is extended to support a new URI scheme providing for indication of a session cookie to be embedded into the browser, as well as an embedded URI to be processed by the browser after the indicated session cookie has been loaded into the browser. After the browser has been extended to handle the new URI scheme, a URI using the new scheme is passed to the browser as a command line parameter by a separate application program. The extended browser processes the new scheme URI, extracting the session cookie data and an embedded URI to be subsequently loaded. A client application separate from the browser may authenticate the user prior to the user requesting access to a secure Web page through the browser. The results of such background authentication steps, which are performed transparently with regard to the user, are then provided to the browser from the non-browser program, in order that the user need not re-supply them. Such previously obtained authentication credentials may be loaded by the non-browser application into the browser program on behalf of the user. Such user authentication credentials may be passed to the browser through a session cookie indicated to the browser using the new URI scheme disclosed herein.