<select name ='cat' size="1">  
<?php
$result = mysql_query("select cat from catprod order by cat");
while ($row = mysql_fetch_object($result)) {
 ?>
<option value="<?php echo $row->cat;?>"><?php echo $row->cat;?></option>
<?php
}
?> 
</select>
<?php
mysql_free_result($result);
?>

$connexion = mysql_connect("****","****","****");
mysql_select_db("****",$connexion); 

$req = "select cat from catprod order by cat"; 
$res=mysql_query($req); ?>
<select name ='cat' size="1">
  <? while( $ess = mysql_fetch_object($res) ) { $cat = $ess->genre; ?>
  <OPTION VALUE><?print ($cat);?></OPTION > <? } ?> </select >