php AJAX实例根据邮编自动完成地址信息

Enter A United States Zipcode, Then Tab

Enter Zipcode:
City:
State:

以上是客户输入页面，下面是服务端的处理页面'zipcode.PHP
$dbuser = 'root';
$dbpass = '111111';
$cn = mysql_connect("localhost", $dbuser, $dbpass);
$db = mysql_select_db("ajax");
$sql = "select city, state from zipcodes where zipcode = " . $_REQUEST['zip'];
$rs = mysql_query($sql);
$row = mysql_fetch_array($rs);
echo $row['city'] . "|" . $row['state'];
mysql_close($cn);
?>
当客户输入一个POSTCODE后，zipcode.PHP就接收到它，然后进行从数据表中取出对应的资料，再按一定的格式返回给客户端（此处是以 | 分隔）。最后客户端接收返回的资料，显示在页面上。
if(response.indexOf('|' != -1)) {
update = response.split('|');
document.getElementById("city").value = update[0];
document.getElementById("state").value = update[1];