一個比較簡單的問題，請給以解決

Question

<script language="javascript">
function work()
{document.department.submit();
}</script>
<?
mysql_connect("localhot","root","root");
mysql_select_db("database");
$result=mysql_query("select * from department");
?>
<form name="department"   action="work.php"  >  
<select name="department" onchange="work();">
<?
while($rows=@mysql_fetch_array($result)){
echo "<option value='$rows[department_id]'>$rows[department_name]</option>";
}
?>
</select>
</form>
___________________________________
<?
//work.php
mysql_connect("localhot","root","root");
mysql_select_db("database");
$sql="select * from department where department_id=$department"
$result=mysql_query($sql);
while($rows=@mysql_fetch_array($result))
echo $rows["worker_name"];?>