An HTTP User Agent Header is also sent to the server ,when a browser connects to a server,. This header contains
information about the browser (like browser type and version
number). The BrowserType object then compares the information in
the header with information in a file on the server called "Browscap.ini"
You can use the BrowserType object to list the properties
of the matching browser if there is a match between the browser type and version number
sent in the header and the information in the "Browsercap.ini"
file .It will set every property to "UNKNOWN" if there is no match for the browser
type and version number in the Browscap.ini file.