This is done with the use of Dynamic Data Exchange (DDE),
for the OS/2 version of Netscape 2.02 understands just the
same DDE commands as the Windows versions do. These commands are
(horribly) documented at
http://developer.netscape.com/library/documentation/communicator/DDE
These documents assume a detailed knowledge of how DDE works,
and believe me, some things ARE different on OS/2.