Data processing system, data processing method, and printer

A data processing method for processing data between a point-of-sales terminal device, a printer, and a server, the data processing method comprising:

• when a terminal communication path satisfies a previously set terminal communication condition:
• connecting the point-of-sales terminal device to the server through the terminal communication path;
• executing by the point-of-sales terminal device a server-side markup language file of the server through a web browser, the server-side markup language file including a script configured to call one or more functions, the one or more functions comprising determining a price of a product based on an identifier of the product;
• when the terminal communication path does not satisfy the terminal communication condition:
• connecting the point-of-sales terminal device to the printer through a printer communication path;
• sending by the printer to the point-of-sales terminal device a printer-side markup language file as a server when the printer is connected to the point-of-sales terminal device, the printer-side markup language file including a script configured to also call the one or more functions;
• executing by the point-of-sales terminal device the printer-side markup language file of the printer through the web browser when the point-of-sales terminal device receives the printer-side markup language file from the printer;
• determining, by the point-of-sales terminal device, the price of the product based on the identifier of the product when the point-of-sales terminal device executes the script regardless of whether the terminal communication path satisfies the terminal communication condition;
• sending, by the point-of-sales terminal device, a request to the printer to print a receipt for the product;
• and
• printing, by the printer, a receipt in response to receiving the request from the point-of-sales terminal device.

A printer connectable to a server and a point-of-sales terminal device, the printer comprising:

• a printer storage configured to store printer-side master data and a printer-side markup language file, the printer-side markup language file including a script configured to call one or more functions, the one or more functions including a receipt printing function;
• the printer configured to:
• act as a server;
• connect to the point-of-sales terminal device through a printer communication path at least when a terminal communication path connecting the point-of-sales terminal device to the server does not satisfy a previously set terminal communication condition;
• and
• send the printer-side markup language file to the point-of-sales terminal device when the printer is connected to the point-of-sales terminal device, the printer-side markup language file being structured so as to be executable by the point-of-sales terminal device using a web browser,
• print a receipt in response to receiving a request from the point-of-sales terminal device to print a receipt for a product, the request being generated when the point-of-sales terminal device executes the script.