Thinkphp で州と市区町村の 3 段階の連携を実現

 public function index(){
        $province = M('Tree')->where ( array('pid'=>1) )->select ();
        $this->assign('province',$province);
        $this->display();
    
    }
    public function getRegion(){
        $Region=M("Tree");
        $map['pid']=$_REQUEST["pid"];
        $map['type']=$_REQUEST["type"];
        $list=$Region->where($map)->select();
        echo json_encode($list);
    }

<select name="province" id="province" onchange="loadRegion(&#39;province&#39;,2,&#39;city&#39;,&#39;{:U(&#39;Index/getRegion&#39;)}&#39;);">
       <option value="0" selected>省份/直辖市</option><volist name="province" id="vo"> 
       <option value="{$vo.id}" >{$vo.name}</option></volist>
    </select>          
    <select name="city" id="city"  onchange="loadRegion(&#39;city&#39;,3,&#39;town&#39;,&#39;{:U(&#39;Index/getRegion&#39;)}&#39;);">
      <option value="0">市/县</option>
    </select>
<select name="town" id="town">
      <option value="0">镇/区</option>
    </select>

function loadRegion(sel,type_id,selName,url){
jQuery("#"+selName+" option").each(function(){
jQuery(this).remove();
});
jQuery("<option value=0>请选择</option>").appendTo(jQuery("#"+selName));
if(jQuery("#"+sel).val()==0){
return;
}
jQuery.getJSON(url,{pid:jQuery("#"+sel).val(),type:type_id},
function(data){
if(data){
jQuery.each(data,function(idx,item){
jQuery("<option value="+item.id+">"+item.name+"</option>").appendTo(jQuery("#"+selName));
});
}else{
jQuery("<option value=&#39;0&#39;>请选择</option>").appendTo(jQuery("#"+selName));
}
}
);
}
</script>

DROP TABLE IF EXISTS `tp_tree`;
CREATE TABLE `tp_tree` (
 `id` int(5) unsigned NOT NULL AUTO_INCREMENT,
 `pid` int(5) unsigned NOT NULL DEFAULT '0',
 `name` varchar(120) DEFAULT NULL,
 `type` tinyint(1) DEFAULT '2',
 PRIMARY KEY (`id`)
) ENGINE=MyISAM AUTO_INCREMENT=3410 DEFAULT CHARSET=utf8;