foreach (("partnumber", "description", "name", "validuntil", "invnumber")) {
$columns{$_} = $callback . "\&sortby=${_}\&sortasc=";
if ($form->{"sortby"} eq $_) {
foreach (("partnumber", "description", "name", "validuntil", "invnumber")) {
$columns{$_} = $callback . "\&sortby=${_}\&sortasc=";
if ($form->{"sortby"} eq $_) {