@sort_by = $cgi->param('sort_by');
$sort_by[0] = $default_sort_by if !$sort_by[0] && defined($default_sort_by);
foreach my $sort (@sort_by) {
@sort_by = $cgi->param('sort_by');
$sort_by[0] = $default_sort_by if !$sort_by[0] && defined($default_sort_by);
foreach my $sort (@sort_by) {