匹配来自mysql的检索结果的下拉列表

I have an error here, the data retrived from mysql database and listed in listbox or dropdown, when i need to update my form i get the result after refresh.

I have tried but need to sortout

<?
include("connect.php");
mysql_select_db("joblisting") or die(mysql_error());
$result = mysql_query("SELECT * FROM positiontitle") or die(mysql_error());
$ans=$positiontitle;
echo $ans;
?><select size=1 name="positiontitle" id="positiontitle"><?
echo '<option value="'.$ans.'">';
echo "</option>";
while ($row = mysql_fetch_array($result))
{
  echo "<option>";
  echo $row['positiontitle'];
  echo "</option>"; 
}
echo "<br />";

?>

where are you defining $positiontitle ? shouldn't it be $_POST['positiontitle']?