PHP dropdown sticky

[Zippy]

I have a database populated drop down list. \[code\]$options4=""; while ($row = mysql_fetch_array($result)) { $id=$row["Client_Code"]; $thing=$row["Client_Full_Name"]; $options4.="<OPTION VALUE=http://stackoverflow.com/questions/2013293//"$id, $thing\">".$thing; } ?> <FORM name="form" action="<?php echo $_SERVER['PHP_SELF']; ?>" method="POST"> <SELECT NAME="ClientNamefour" OnChange="this.form.submit()"> <OPTION VALUE=http://stackoverflow.com/questions/2013293/0>Client <?php echo $options4?> </SELECT> </FORM>\[/code\]Once this changes it pulls a client name from a database and brings up some information there is a form that can be filled out to insert more information into a database. Once that form is filled out this page sends the information to another page with the code to insert the data into the database. Then I am using a header at the end of that code to send it back to this page. But when it comes back to this page I want it to comeback to the client they selected before and not a blank screen. So how do I make a DB populated list automatically comeback to the previous selection using php?