A client terminal can control a printer even when the network connection to a web server is interrupted, and can convert character codes using a simple configuration. The client terminal having a standard web browser and connected to a web server and a printer has a web page acquisition unit that uses the web browser to acquire a web page with an embedded printer control script from the web server; a web page display unit that displays the acquired web page and run the printer control script; a character code conversion unit that uses the printer control script to convert script character codes to printer character codes, which is a character code for the device; and a command transmission unit that sends a command containing the converted printer character codes to the printer.