php AJAX实例根据邮编自动完成地址信息

　　<script>
function createRequestObject() {
var ro;
var browser = navigator.appName;
if(browser == Microsoft Internet Explorer){
ro = new ActiveXObject(Microsoft.XMLHTTP);
}else{
ro = new XMLHttpRequest();
}
return ro;
}
var http = createRequestObject();
function sndReq(zip) {
http.open(get, zipcode.PHP?zip=+zip);
http.onreadystatechange = handleResponse;
http.send(null);
}
function handleResponse() {
if(http.readyState == 4){
var response = http.responseText;
var update = new Array();
update = response.split();
document.getElementById(city).value = update[0];
document.getElementById(state).value = update[1];
}
}
}
</script>
<h3>Enter A United States Zipcode, Then Tab</h3>
<table align=center>
<tr>
<td>Enter Zipcode:</td>
<td><input type=text id=zipcode name=zipcode onBlur=sndReq(this.value);/></td>
</tr>
<tr>
<td>City:</td>
<td><input type=text id=city name=city/></td>
</tr>
<tr>
<td>State:</td>
<td><input type=text id=state name=state/></td>
</tr>
</table>
以上是客户输入页面，下面是服务端的处理页面zipcode.PHP
<?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];