Echo dropdown selection

[webweever]

I'm trying to do a couple of things using the dropdown list below. I have a table with id, rank, and amount.

 

1. I need to echo the amount that corresponds to the rank selected from the dropdown list.

2. I also need to put the amount value in a variable so I can do some math with it later on.

 

I've got the dropdown pulling the rank values from the db just not sure how to make it do the rest I'm trying to do.

 

Any help would be greatly appreciated

 

 

<?php
db($host,$db_name,$user,$pass);
function db($host,$db_name,$user,$pass)
{
global $link;
$link=mysql_connect ("$host","$user","$pass");
if(!$link){die("Could not connect to MySQL");}
mysql_select_db("$db_name",$link) or die ("could not open db".mysql_error());
}


$sql="SELECT * FROM dlaw";
$result=mysql_query($sql);

$options="";

while ($row=mysql_fetch_array($result)) {

    $rank=$row["rank"];
    $options.="<OPTION VALUE=\"$rank\">".$rank.'</option>';
}
?>
		<SELECT NAME=rank><OPTION VALUE=0>Select Rank<?=$options?></SELECT>