An image forming apparatus, comprising: a storage section; and a control section that employs a hardware resource to conduct a controlling operation in regard to an image forming operation; wherein the control section is capable of executing a first process of apparatus controlling firmware that controls a default display screen, which provides both a status display and a button for accepting an instruction in regard to the image forming operation, to be displayed on a display section, and wherein the control section is capable of executing a second process of a Web display screen application program that controls a customizable display screen, which can be arbitrarily customized and which provides both the status display and the button for accepting an instruction, to be displayed on the display section, wherein the second process is separate from the first process; and wherein, based on the Web display screen application program, the control section designates any one of a plurality of default display screens to be controlled by the apparatus controlling firmware as a designated default display screen, so as to allow a screen calling operation for calling out the any one of the plurality of default display screens as the designated default display screen to be conducted; and wherein, when the Web display screen application program instructs the apparatus controlling firmware to conduct the screen calling operation in a state in which the Web display screen application program displays the customizable display screen onto the display section, the control section outputs the designated default display screen onto the display section, based on the apparatus controlling firmware. a storage section; and a control section that employs a hardware resource to conduct a controlling operation in regard to an image forming operation; wherein the control section is capable of executing a first process of apparatus controlling firmware that controls a default display screen, which provides both a status display and a button for accepting an instruction in regard to the image forming operation, to be displayed on a display section, and wherein the control section is capable of executing a second process of a Web display screen application program that controls a customizable display screen, which can be arbitrarily customized and which provides both the status display and the button for accepting an instruction, to be displayed on the display section, wherein the second process is separate from the first process; and wherein, based on the Web display screen application program, the control section designates any one of a plurality of default display screens to be controlled by the apparatus controlling firmware as a designated default display screen, so as to allow a screen calling operation for calling out the any one of the plurality of default display screens as the designated default display screen to be conducted; and wherein, when the Web display screen application program instructs the apparatus controlling firmware to conduct the screen calling operation in a state in which the Web display screen application program displays the customizable display screen onto the display section, the control section outputs the designated default display screen onto the display section, based on the apparatus controlling firmware.