运用ajax技术写联动的效果

客服端的页面代码:

$conn=mysql_connect("localhost","root",'root');
if($conn){
    $sql="use privince";
    mysql_query($sql);
    $sql="set names utf8";
    mysql_query($sql);
    $sql="select * from privince";
    $res=mysql_query($sql);
    $privice_arr=array();
    while($row=mysql_fetch_assoc($res)){
        $privince_arr[]=$row;
    }
    mysql_free_result($res);
    mysql_close($conn);

}else{
    die(mysql_error());
    exit;
}

?>





    var xhr="";
    function getXhr(){
        if(XMLHttpRequest){
            xhr=new XMLHttpRequest();
        }else{
            xhr=new ActiveXObject("Microsoft.XMLHTTP");
        }


    }
    function chuli(){
        if(xhr.readyState==4){
            if(xhr.status==200){
                var res=eval("("+xhr.responseText+")");
                if(res[0].action=='privince'){  //判断动作，看是创建省，还是市的dom节点

                    var city=$('city');
                    city.length=0;
                    var obj=document.createElement("option");
                        obj.innerHTML="请选择市...";
                        city.appendChild(obj);
                    for(var i=1;i                        var city_obj=document.createElement("option");
                        city_obj.value=res[i].city_name;
                        city_obj.innerHTML=res[i].city_name;
                        city.appendChild(city_obj);
                    }

                }else if(res[0].action=='city'){


                    var county=$('county');
                    county.length=0;
                    var obj=document.createElement("option");
                    obj.innerHTML="请选择县...";
                    county.appendChild(obj);
                    for(var i=1;i                        var county_obj=document.createElement("option");
                        county_obj.value=res[i].county_name;
                        county_obj.innerHTML=res[i].county_name;
                        county.appendChild(county_obj);
                    }

                }

            }
        }
    }


    function change(obj){
        getXhr();
        //obj用于判断选择的动作和取得用户的选择值，
        quyu=$(obj).value;

        var uri="privinceContro.php?action="+obj+"&area="+encodeURI(quyu)+"date="+new Date();//这里为了防止在将数据传给控制器的时候出现乱码而出现取数据的错误，而用encondeURI函数转码

        xhr.open("get",uri,true);
        xhr.onreadystatechange=chuli;
        xhr.send(null);

    }

    function $(id){
        return document.getElementById(id);
    }





    请选择省份...

    " >
        
    


  



请选择市...

  


请选择县...

控制器的代码：

$action=trim($_GET['action']);
$quyu=trim($_GET['area']);

$conn=mysql_connect("localhost","root",'root');
if($conn){
    $info='';
    $sql="use privince";
    mysql_query($sql);
    $sql="set names utf8";
    mysql_query($sql);

    if($action=='privince'){
        $sql="select * from cities where privince_id =(select privince_id from privince where privince_name='$quyu')";
        $res=mysql_query($sql);
        $privince_arr=array();
        while($row=mysql_fetch_assoc($res)){
            $privince_arr[]=$row;
        }
        $info.='[{"action":"privince"},';
        for($i=0;$i            if($i==count($privince_arr)-1){
                $info.='{"city_name":"'.$privince_arr[$i]['city_name'].'"}]';
            }else{
                $info.='{"city_name":"'.$privince_arr[$i]['city_name'].'"},';
            }
        }
        echo $info;
        exit;
    }else if($action=='city'){

        $sql="select * from county where city_id =(select city_id from cities where city_name='$quyu')";
        file_put_contents("D:\myenv\apache\htdocs\ajax\log.txt",$sql,FILE_APPEND);
        $res=mysql_query($sql);
        $privince_arr=array();
        while($row=mysql_fetch_assoc($res)){
            $privince_arr[]=$row;
        }
        $info.='[{"action":"city"},';    //给客服端发送动作的类型
        for($i=0;$i            if($i==count($privince_arr)-1){
                $info.='{"county_name":"'.$privince_arr[$i]['county_name'].'"}]';
            }else{
                $info.='{"county_name":"'.$privince_arr[$i]['county_name'].'"},';
            }
        }
        echo $info;
        exit;
    }
}else{
    die(mysql_error());
    exit;
}

数据库：

create database pricince default charset=utf8;

use privince;

create table privince(
    privince_id int unsigned primary key auto_increment not null,
    privince_name varchar(24) not null default ''

)

create table cities(
    city_id int unsigned primary key auto_increment not null,
    city_name varchar(24) not null default '',
    privince_id int not null default ''
);

create table county(
    county_id int unsigned primary key auto_increment not null,
    county_name varchar(24) not null default ''
    city_id int not nul default ''
);

insert into privince (privince_name) values('四川省'),('福建省'),('广东省');
insert into cities (city_name,privince_id) values
('成都市',1),
('遂宁市',1),
('泸州市',1),
('福州市',2),
('泉州市',2),
('广州市',3),
('珠海市',3);

insert into county (county_name,city_id) values
('双流县',1),
('金牛区',1),
('射洪县',2),
('大英县',2),
('泸县',3),
('合江县',3)，
('仓山区',4),
('永泰县',4),
('晋江',5),
('石狮',5),
('越秀区',6),
('海珠区',6),
('斗门区',7),
('香港区',7);