<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<script type="text/javascript">
window.onload=function(){
function $(id) {
return document.getElementById(id);
}
function getXHR() {
//1、创建ajax引擎
var oAjax;
if(window.XMLHttpRequest) {
oAjax = new XMLHttpRequest();
} else {
oAjax = new ActiveXObject("Microsoft.XMLHTTP");
}
return oAjax;
}
$('sheng').onchange=function(){
var oAjax=getXHR();
if(oAjax){
var url='/citylist.php?time='+new Date+'&name='+$('sheng').value;
oAjax.open('GET', url, true);
oAjax.send(null);
oAjax.onreadystatechange=function(){
//alert('现在的状态'+oAjax.readyState);
if(oAjax.readyState==4){
if(oAjax.status==200){
var arr=eval(oAjax.responseText);
//alert(arr.length);
$('city').length=0;
var oPtion=document.createElement('option');
oPtion.innerHTML='--城市--';
$('city').appendChild(oPtion);
for(var i=0;i<arr.length;i++){
var oPtion=document.createElement('option');
oPtion.innerHTML=arr[i].city;
$('city').appendChild(oPtion);
}
}
//alert(oAjax.responseText);
//$('inf').innerHTML=oAjax.responseText;
}
}
}
}
}
</script>
</head>
<body>
<form action="" method="post">
<select id="sheng">
<option value="s">--省份--</option>
<option value="gx">广西</option>
<option value="gd">广东</option>
</select>
<select id="city">
<option value="">--城市--</option>
</select>
<select id="xian">
<option value="">--县城--</option>
</select>
</form>
</body>
</html>
三级联动处理函数:citylist.php
<?php
//这里两句话很重要,第一讲话告诉浏览器返回的数据是xml格式
header("Content-Type: text/text;charset=utf-8");
//告诉浏览器不要缓存数据
header("Cache-Control: no-cache");
$sheng=$_GET['name'];
file_put_contents("d:/mylog.log",$sheng."\r\n",FILE_APPEND);
if($sheng=='gx'){
echo '[{"city":"南宁"},{"city":"桂林"},{"city":"柳州"}]';
}
else if($sheng=='gd'){
echo '[{"city":"广州"},{"city":"东莞"},{"city":"佛山"}]';
}
?>