my @dropdown = ('Option 1','Option 2','Option 3');
foreach $op (@dropdown) {
  if ($op eq $in{'dropdown}) { # I use cgi-lib.pl still...
    $dropdown .= "<option selected>$op</option>\n";
  } else {
    $dropdown .= "<option>$op</option>\n";
  }
}
# later on insert $dropdown somewhere on you're 
# HTML response page...