CLIENT TERMINAL, SERVER, SERVER-CLIENT SYSTEM, COOPERATION PROCESSING METHOD, PROGRAM AND RECORDING MEDIUM

An application on a client terminal transmits application session information indicating a state of the application itself and an application signature proving the identity of the application to a browser. The browser transmits the application session information and the application signature to a server. The server generates an HTML page in which a script specifying an operation to be performed by the application is inserted and server session information and transmits the HTML page and the server session information to the browser along with the application signature received from the browser. When the script is activated, the browser passes the information received from the server to the application. The application performs processing according to the server session information only if the application signature passed from the browser is an application signature generated by the application itself.