Código PHP:
if(isset($_SESSION['select']))
{
$clave=array_search($_GET['sele'],$_SESSION['select']);
unset($_SESSION['select'][$clave]);
$l=0;
for ($s=0;$s<count($_SESSION['select']);$s++)
{
if(isset($_SESSION['select'][$s]))
{
$sel[$l++]=$_SESSION['select'][$s];
}
else
$sel=NULL;
}
unset($_SESSION['select']);
session_register('select');
for($s=0;$s<count($sel);$s++)
{
$_SESSION['select'][$s]=$sel[$s];
}
}