# Read the cookie called 'snakeoil-nav' that the client sent us.
# $cgi is a CGI.pm object.
my $cookie = $cgi->cookie(-name => 'snakeoil-nav');
# If the cookie is blank, set it with a default.
if (defined ($cookie)) {
  $cookie = $cgi->cookie(-name => 'snakeoil-nav',
                         -value => '/nav.html',
                         -expires => '+3d',
                         -domain => '.interhack.net');
}