省市县三级联动实现代码

<td class="item_input">

<select name="province" id="province">

<option value="0">=请选择=</option>

<foreach name="provincelist" item="vo">

<option value="{$vo['area_id']}">{$vo.name}</option>

</foreach>

</select>

<span> 省</span>

<select name="city" id="city" style="display:none">

</select>

<span id="sitecity" style="display:none"> 市</span>

<select name="district" id="district" style="display:none">

</select>

<span id="sitedistrict" style="display:none"> 县</span>

</td>

<script>

$(function(){

$("#province").change(function(){

var province = $("#province").val();

$.get("{:U("Companysite/findcity")}" , {province:province} , function(str){

$('#city').empty();

$("#district").empty();

$("#district").append("<option value='0'>=请选择=</option>");

$("#city").show();

$("#sitecity").show();

$("#city").append(str.info);

} , 'json');

});

$("#city").change(function(){

var city = $("#city").val();

$.get("{:U('Companysite/finddistrict')}" , {city:city} , function(str){

$("#district").empty();

$("#district").show();

$("#sitedistrict").show();

$("#district").append(str.info);

} , 'json');

});

</script>

public function findcity(){

$province =intval($_GET['province']);

$citylist = M('area')->where("parent_id=".$province)->select();

$str = "<option value='0' selected='selected'>=请选择=</option>";

if($citylist){

foreach($citylist as $key=>$value){

if($key==0){

$str.="<option value=".$value['area_id']." >".$value['name']."</option>\r\n";

}else {

$str.="<option value=".$value['area_id'].">".$value['name']."</option>\r\n";

}

}

}else {

$str ="<option value='0'>=无城市=</option>\r\n";

}

$this->success($str);

}