Described is a system and method comprising a content format by which client programs running on a main computer system may provide data to various types of auxiliary display devices. The format, which may be XML-based, provides menu pages comprising a list of selectable items, content pages comprising text and images, and dialog pages providing text, images and one or more actionable options. The text and images may be accompanied by requested formatting information, e.g., specifying emphasis, color, alignment, wrapping and/or fit to the screen. An auxiliary device can parse the content to display as much as possible, particularly information recognized (via content tags) as significant, and use the formatting information to the extent of its capabilities. Virtual buttons may be defined for page navigation and/or item selection. Pages of the content format may be cached for operation when the main computer system is offline from the auxiliary display device.