Assembly: System.Web (in system.web.dll)
Property ValueThe approximate width of the display, in characters. The default is 12.
The returned value can be derived from the assumed character size and actual screen pixel size. The algorithm for determining the width uses a combination of the default font sizes (from a .config file), device-specific sizes (again, from a .config file), and explicit headers sent by the devices. These values are not necessarily exact (especially for variable-width fonts, these values are approximate). Some devices might rely on internal default values, which only approximate the actual width.