Refreshing a dropdown list when selecting another dropdown list.

[eluser]theighost[/eluser]
the first file changed to:

<?
//set IE read from page only not read from cache
header ("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
header ("Last-Modified: " . gmdate("D, d M Y H:i") . " GMT");
header ("Cache-Control: no-cache, must-revalidate");
header ("Pragma: no-cache");

header("content-type: application/x-javascript; charset=tis-620");

$data=$this->uri->segment(3);
$data=$this->uri->segment(4);

//set database
$dbhost = "localhost";
$dbuser = "";
$dbpass = "";
$dbname = "test";
mysql_pconnect($dbhost,$dbuser,$dbpass) or die ("Unable to connect to MySQL server");

if ($data=='states') { // first dropdown
echo "<select name='states'>\n";
echo "<option value='0'>==== choose state ====</option>\n";
$result=mysql_db_query($dbname,"select `id`, `state` from states order by `state`");
while(list($id, $name)=mysql_fetch_array($result)){
echo "<option value=\"$id\" >$name</option> \n" ;
}
} else if ($data=='cities') { // second dropdown
echo "<select name='cities' >\n";
echo "<option value='0'>====choose cities ====</option>\n";
$result=mysql_db_query($dbname,"SELECT `id`, `city` FROM cities WHERE `state_id` = '$val' ORDER BY `city` ");
while(list($id, $name)=mysql_fetch_array($result)){
echo "<option value=\"$id\" >$name</option> \n" ;
}
}
echo "</select>\n";
?&gt;




the second changed to :


&lt;?
echo "&lt;form name=sel&gt;\n";
echo "States : <font id=states><select>\n";
echo "<option value='0'>============</option> \n" ;
echo "</select></font>\n";

echo "Cities : <font id=cities><select>\n";
echo "<option value='0'>=== none ===</option> \n" ;
echo "</select></font>\n";
?&gt;

[removed]
function Inint_AJAX() {
try { return new ActiveXObject("Msxml2.XMLHTTP"); } catch(e) {} //IE
try { return new ActiveXObject("Microsoft.XMLHTTP"); } catch(e) {} //IE
try { return new XMLHttpRequest(); } catch(e) {} //Native Javascript
alert("XMLHttpRequest not supported");
return null;
};

function dochange(src, val) {
var req = Inint_AJAX();
req.onreadystatechange = function () {
if (req.readyState==4) {
if (req.status==200) {
document.getElementById(src)[removed]=req.responseText; //retuen value
}
}
};
req.open("GET", "state.php/"+src+"/"+val); //make connection
req.setRequestHeader("Content-Type", "application/x-www-form-urlencoded;charset=iso-8859-1"); // set Header
req.send(null); //send value
}

window.onLoad=dochange('states', -1); // value in first dropdown
[removed]



and it didnt work plz help