这是个不错多级联动插件,用起来比较简单实用,如果非要吹毛求疵的话,就是需要加载文件少多一点.
这个是插件作者的博客,里有有实例和下载,大家想想要详细了解可以去看看
http://www.36ria.com/2955
 
因为原版里是连接数据库,想下到本地看效果很费劲.我这里写个简单用法,用于给新手立马上手能用.

test.html

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd" >
< html xmlns ="http://www.w3.org/1999/xhtml" >
< head >
< meta http-equiv ="Content-Type" content ="text/html; charset=utf-8" />
< title >$.ld——jquery多级联动插件 V1.0 title>
< link href ="style/css/base.css" rel ="stylesheet" type ="text/css" />
< link href ="style/css/demo.css" rel ="stylesheet" type ="text/css" />
head>
< body >
< div id ="header" class ="clearfix" >
< div id ="logo" class ="l" > < img src ="style/p_w_picpaths/logo.png" /> div>
< div class ="l" >
                 < h2 >$.ld——jquery多级联动插件 V1.0 h2>
                 < p >作者：明河共影，博客： < a href ="http://www.36ria.com/" >RIA之家 a> p>
                 < p >插件文档： < a href ="http://www.36ria.com/2955" >http://www.36ria.com/2955 a> p>        
         div>
div>
< h2 >示例1：最基础的示例演示，读取json h2>
< table width ="700" border ="0" cellspacing ="0" cellpadding ="0" class ="tab1" >
     < tr >
     < td >国家 td>
     < td > < select     class ="ld-select-1" name ="country" >
             < option value="" >请选择你的国家 option>
         select>
        
         td>
         < td >省份 td>
         < td > < select     class ="ld-select-1" name ="province" >
             < option value="" >请选择你的省份 option>
         select>
         td>
         < td >城市 td>
         < td > < select class ="ld-select-1" name ="city" >
             < option value="" >请选择你的城市 option>
         select>
         td>
         < td >区县 td>
         < td > < select class ="ld-select-1" name ="county" >
             < option value="" >请选择你的区县 option>
         select>
         td>
     tr>
table>
< code >
$(".ld-select-1").ld({ajaxOptions : {"url" : "get_region.php"}, < br />
style : {"width" : 120} < br />
});
code>

    

< script src ="js/jquery-1.4.2.min.js" > script>
< script src ="js/jquery.ld.js" > script>
< script type ="text/javascript" >
$(function(){
//示例1
$(".ld-select-1").ld({ajaxOptions : {"url" : "get_region.php"},
                style : {"width" : 120}
                                            });    
})
script>
body>
html>




get_region.php

ob_start();
/*
function runSQL($rsql) {
$hostname = 'localhost';// 数据库服务器
$username = 'root';    // 数据库用户名
$password = '123';         // 数据库密码
$dbname     = 'ld';     // 数据库名
$connect = mysql_connect($hostname,$username,$password) or die ("Error: could not connect to database");
$db = mysql_select_db($dbname);
mysql_query('set names utf8');
$result = mysql_query($rsql);    
return $result;
mysql_close($connect);
}
*/
include("include/JSON.php");
/*if(isset($_GET['parent_id'])){
$where = "WHERE parent_id = ".$_GET['parent_id']." ";
}else{
$where = "WHERE parent_id = 0 ";
}*/

/*$sql = "SELECT * FROM region $where";
$result = runSQL($sql);*/

$data_type = "json";
if(isset($_GET['data_type'])){
$data_type = $_GET['data_type'];
}
if($_GET['parent_id'] == 0){
$rows = array(array('region_id'=>1,'region_name'=>"我X1"),array('region_id'=>2,'region_name'=>"我X2"),array('region_id'=>3,'region_name'=>"我X3"),array('region_id'=>4,'region_name'=>"我X4"));
}else{
$rows = array(array('region_id'=>1,'region_name'=>"我T1"),array('region_id'=>2,'region_name'=>"我T2"),array('region_id'=>3,'region_name'=>"我T3"),array('region_id'=>4,'region_name'=>"我T4"));    
}

if($data_type == "json"){
$json_str = "[";
$json = array();
foreach($rows as $row) {
/*    $r = array('region_id' => $row['region_id'],
                         'region_name' => $row['region_name']);*/
    $json[] = JSON($row);
}
$json_str .= implode(',',$json);
$json_str .= "]";
echo $json_str;    
}else if($data_type == "xml"){
        header("Content-type: text/xml;");
$xml = "";
$xml .= "";
while ($row = mysql_fetch_array($result)) {
    $xml .= "";
     $xml .= "".$row['region_id']."";
     $xml .= "".$row['region_name']."";
    $xml .= "";
}
$xml .="";
echo $xml;    
}
?>

这里简单说明下  我为了下载后就能看到效果 就把原版的数据库连接全部注释了  而用数组来充当数据库返回结果  如果你是连接数据库的话那就把注释去掉改写下 或者去下原版吧
还有这里我贴的是我改的两个文件 但并不是有这两个就能用 我把例子上传到这里 想要就去下吧
jquery多级联动插件及实例