The process to be performed in accordance with the type of the detected marker may be of any content. The process performed in step S22 may be, for example, a process of launching a predetermined application program with which the operation device 20 can be used. The process performed in step S22 may be a process of obtaining a predetermined application program with which the operation device 20 can be used. That is, the control section 14 may access a predetermined external device (e.g., a server capable of communicating with the portable device 1 via a network) to obtain the application program. Then, the obtained application program may be executed automatically. The process performed in step S22 may be a process of obtaining a web page from a server and displaying the web page on the display 2. For example, the web page to be displayed may be a web page for downloading an application program, or an advertisement of the vendor of the operation device 20.
Note that the control section 14 may change the type of the process to be performed depending on the type of the marker detected. That is, depending on the type of the marker detected, the control section 14 may perform one of the process of launching an application program, the process of obtaining an application program, and the process of displaying a web page. Depending on the type of the marker detected, the control section 14 may change the content of the process within the same process type. That is, depending on the type of the marker detected, the control section 14 may change the application program to be launched, change the application program to be obtained, or change the web page to be displayed.