新建主页面，如下
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<script src="../wenjian/jquery-2.2.3.min.js"></script>
</head>
<body>
<select id="sheng">
<option>请选择</option>
</select>
<select id="shi">
<option >请选择</option>
</select>
<select id="qu">
<option >请选择</option>
</select>
</body>
</html>
<script>
$.ajax({
data: {parent_id: 0}, //发送的数据
dataType: "json", //返回值的类型 text为string型
type: 'post', //发送请求的方法(get)
url: 'sheng_l.php',//发送请求的地址
success: function (data) {//发送成功时的回调函数
// console.log(data);
for (var i in data) {
$("#sheng").append("<option value='"+ data[i][2] +"'>" + data[i][1] +"</option>")
}
}
})
$(document).ready(function () {
$("#sheng").change(function () {
$("#shi").get(0).options.length= 1;
// $("#qu").get(0).options.length= 1;
var data = $("#sheng").find("option:selected").val();
$.ajax({
data:{parent_id:data},
type:"post",
dataType:"json",
url:"sheng_l.php",
success:function (data) {
for(var i in data){
$("#shi").append("<option value='" + data[i][2] +"'>" + data[i][1] +"</option>")
}
}
})
})
})
$(document).ready(function () {
$("#shi").change(function () {
$("#qu").get(0).options.length= 1;
var data = $("#shi").find("option:selected").val();
$.ajax({
data:{parent_id:data},
type:"post",
dataType:"json",
url:"sheng_l.php",
success:function (data) {
for (var i in data){
$("#qu").append("<option value='" +data[i][2] +"'>" +data[i][1] +"</option>")
}
}
})
})
})
建立处理页面，如下
/**
* Created by fcc
* User: Administrator
* Date: 2017/10/29
* Time: 20:56
*/
require_once "../wenjian/DBDA.class.php";
$db = new DBDA();
$sql = "select * from region WHERE father_id = {$_POST['parent_id']}";
$result = $db->Query($sql);
echo json_encode($result);