In order to prevent leakage of information, a server supplies a program to be executed by an external client having a Web browser that displays a screen based on Web data to the external client. Based on no operation for a predetermined time in regard to the screen displayed on the Web browser, the program causes the Web browser of the external client to perform a process of deleting an element related to specific content from the Web data corresponding to the screen displayed on the Web browser via a DOM (document object model), and updating the screen displayed on the Web browser with a screen not including the specific content.