edit multiple selected records

[phwae]

I have a multiple select box in a form page. When I retrieve that form to update a record, the multiple select records show selected only if I selected one record. If I have multiple selectons, it does not show anything at all, and therefore, I get blank for this field when I click "Update". Can anyone please let me know how can I correct this problem? Thanks.

My code to show the selected records is below:

<tr bgcolor="#FFFFFF">
<td>Operating system:</td>
<td><select name="os[]" multiple="multiple">
<? while ($os_sys=mysql_fetch_array($osresult))
{
If ($os_sys["os"] == $data["os"])
{
echo "<option value='$os_sys[os]' selected>";
echo ucwords($os_sys['os']);
}
else
{
echo "<option value='$os_sys[os]'>";
echo ucwords($os_sys['os']);
}
}
?>
</select> (press ctrl+down arrow key for multiple selection)</td>
</tr>

[adi]

Here's something i used in a similar situation.
I hope its usefull.

if(isset($_GET['checked']))      //--------------------
{
include("head.php");
$sterse=$_GET['checked'];
foreach($sterse as $val)
{
$sql="DELETE FROM furnizori WHERE cod_furnizor='$val'";
mysql_query($sql);
print"$val sters<br>";
$sql="SELECT cod_furnizor FROM produse WHERE cod_furnizor='$val'";
$rezultat=mysql_query($sql);
$numar=mysql_num_rows($rezultat);
$sql="DELETE FROM produse WHERE cod_furnizor='$val'";
mysql_query($sql);
print "Au fost sterse $numar produse!";
print '<br>';
}
}

The form:

<form method="GET" name="form_sterge" action="furnizori.php">
<input type="checkbox" name="checked[]"  value="'.$row['cod_furnizor'].'" >