ajax三级联动实现代码

script src="../jquery-1.11.2.min.js">/script>
script src="sanji.js">/script>
title>无标题文档/title>
/head>

body>
h1>三级联动/h1>
div id="sanji">/div>

/body>
/html>

// JavaScript Document
$(document).ready(function(e) {
 //找到ID=SANJI的DIV，造三个下拉扔进去
 $("#sanji").html("select id='sheng'>/select>select id='shi'>/select>select id='qu'>/select>");
 
 //加载省的数据
 LoadSheng();
 //加载市的数据
 LoadShi();
 //加载区的数据
 LoadQu();
 
 //给省的下拉加点击事件
 $("#sheng").click(function(){
   //重新加载市
   LoadShi();
   //重新加载区
   LoadQu();
  })
 //给市的下拉加点击事件
 $("#shi").click(function(){
   //重新加载区
   LoadQu();
  })
 
});
//加载省份的方法
function LoadSheng()
{
 //省的父级代号
 var pcode = "0001";
 $.ajax({
  async:false,
  url:"chuli.php",
  data:{pcode:pcode},
  type:"POST",
  dataType:"TEXT",
  success: function(data){
   var hang = data.trim().split("|");
   var str = "";
   for(var i=0;ihang.length;i++)
   {
    var lie = hang[i].split("^");
    str = str+"option value='"+lie[0]+"'>"+lie[1]+"/option>";
   }
   $("#sheng").html(str);
  }
 });
}
//加载市的方法
function LoadShi()
{
 //找市的父级代号
 var pcode = $("#sheng").val();
 $.ajax({
  async:false,
  url:"chuli.php",
  data:{pcode:pcode},
  type:"POST",
  dataType:"TEXT",
  success: function(data){
   var hang = data.trim().split("|");
   var str = "";
   for(var i=0;ihang.length;i++)
   {
    var lie = hang[i].split("^");
    str = str+"option value='"+lie[0]+"'>"+lie[1]+"/option>";
   }
   $("#shi").html(str);
  }
 });
}

//加载区的方法
function LoadQu()
{
 //找区的父级代号
 var pcode = $("#shi").val();
 $.ajax({
  url:"chuli.php",
  data:{pcode:pcode},
  type:"POST",
  dataType:"TEXT",
  success: function(data){
   var hang = data.trim().split("|");
   var str = "";
   for(var i=0;ihang.length;i++)
   {
    var lie = hang[i].split("^");
    str = str+"option value='"+lie[0]+"'>"+lie[1]+"/option>";
   }
   $("#qu").html(str);
  }
 });
}

?php
//给一个父级代号，返回该父级代号下所有的子地区
require "DBDA.class.php";
$db=new DBDA();
$pcode=$_POST["pcode"];


$sql="select areacode,areaname from chinastates where parentareacode='{$pcode}'";
echo $db->StrQuery($sql);

?php
class DBDA
{
 public $host = "localhost";
 public $uid = "root";
 public $pwd = "123";
 public $dbname = "test_123";
 //执行SQL语句返回相应的结果
 //$sql 要执行的SQL语句
 //$type 代表SQL语句的类型，0代表增删改，1代表查询
 function query($sql,$type=0)
 {
  $db = new MySQLi($this->host,$this->uid,$this->pwd,$this->dbname);
  
  $result = $db->query($sql);
  
  if($type)
  {
   //如果是查询，显示数据
   return $result->fetch_all();
  }
  else
  {
   //如果是增删改，返回true或者false
   return $result;
  }
 }
 
 //返回字符串的方法
 public function strquery($sql,$type=1)
 {
  $db = new MySQLi($this->host,$this->uid,$this->pwd,$this->dbname);
  $result = $db->query($sql);
  $arr = $result->fetch_all();
  $str="";
  foreach($arr as $v)
  {
   $str = $str.implode("^",$v)."|";
  }
  
  $str = substr($str,0,strlen($str)-1);
  return $str;

 }
 
 //返回JSON
 function JSONQuery($sql,$type=1)
 {
  $db = new MySQLi($this->host,$this->uid,$this->pwd,$this->dbname);
  $r = $db->query($sql);
  
  if($type==1)
  {
   return json_encode($r->fetch_all(MYSQLI_ASSOC));
  }
  else
  {
   return $r;
  }
 }
}