<?php
session_start();
$date = date('Y');
?>

<form action='test2.php' method='POST'>
<select name='date_test' size='1'>

<?php
$trim_ob =
  array(
    array('I', 31),
    array('II', 30),
    array('III',30),
    array('IV', 31 )
  );
for($i = $date; $i <= $date + 2; $i++)
    {
  foreach($trim_ob as $cle => $valeur)
    {
    $mois = 3 * $cle + 3;
    $trimestre = $i.'-'.$mois.'-'.$valeur[1];
    echo('<option value="'.$trimestre.'"');

    echo('>Trim '.$valeur[0].', '.$i.'</option>');  
    };
    };
if(isset($_SESSION['fix_obj'][7]) && ($_SESSION['fix_obj'][7] == $trimestre))
    {
      echo('selected="selected"');
    };
?>
</select>
<input type='submit' value='Go' />
</form>

<?php
session_start();
$_SESSION['fix_obj'][7] = $_POST['date_test'];
echo $_SESSION['fix_obj'][7];
?>
<p><a href="test.php">Retour</a></p>

$ongoingYear = date('Y');

echo('<select name="quarter" size="1">');
$quarters =
  array(
    array('I',   31),
    array('II',  30),
    array('III', 30),
    array('IV',  31)
  );
for($i = $ongoingYear; $i <= $ongoingYear + 2; $i++){
  foreach($quarters as $numQuarter => $infoQuarter){
    $month = 3 * $numQuarter + 3;
    $formattedQuarter = $i.'-'.$month.'-'.$infoQuarter[1];
    echo('<option value="'.$formattedQuarter.'"');
    if(isset($_SESSION['fix_obj'][7]) && ($_SESSION['fix_obj'][7] == $formattedQuarter)){
      echo(' selected="selected"');
    };
    echo('>trim '.$infoQuarter[0].', '.$i.'</option>');
  };
};
echo('</select>');

$_SESSION['fix_obj'][7] = $_POST['quarter'];

$liste = array();
for ($i=1;$i<15;$i++)
{
   $liste[] = $trimestre[$courant].','.$année;
   if ($courant == 4)
   {
      $courant = 1;
      $annee++;
   } 
   else
   {
      $courant++;
   }
}