원본.php

<script>
function sub(){
f = document.lform;
var x = f.sel1.value;
$.ajax({
type: "POST",
url: "qry_team.php",
data: "teamidx="+x,
success: function(msg){
$("#sp1").html(msg);
}
});
}
</script>

<select name="sel1" onchange="sub();">
<option value="">소속선택</option>
<?
$qr1 = "select * from ${basictb}_member_team order by orders asc";
$q_rlt = mysql_query($qr1);
while ($qteam = mysql_fetch_array($q_rlt) ) {
?>
<option value="<?=$qteam[index_no]?>"><?=$qteam[tname]?></option>
<?
}
?>
</select>

<span id="sp1">
<select name='t_idx'>
<option value=''>선택하세요</option>
</select>
</span>

---------------------------------------------------------

qry_team.php

<?
$dir = "../..";
include "$dir/inc/connect.php";
include "$dir/inc/config.php";
$teamidx = $_POST[teamidx];
mysql_query("set names utf8;");

?>
<select name='t_idx'>
<option value=''>선택하세요</option>
<?
$q = "Select ${basictb}_member.index_no,name from ${basictb}_member,${basictb}_member_grades where grade_isadmin='Y' and ${basictb}_member.memgrade=${basictb}_member_grades.grade_id and grade_isadmin='Y' and memteam='$teamidx'";
$r = mysql_query($q);
while($row = mysql_fetch_array($r))
{ echo "<option value='$row[index_no]'>$row[name]</option>"; }
?>
</select>

동적 셀렉트박스, php, jquery, ajax, select, selectbox