jquery php 省市区联动

JS：

    $("#from_prov_id,#from_city_id").change(function () {
        var current_prov_id = $(this).val();
        var _this = this;
        $.ajax({
            type:'get',
            url:"{:url('getarea')}?id="+current_prov_id,
            success:function (data) {
                var data = JSON.parse(data);
                if (data.list2==''){
                    $('#from_area_id option').remove();
                    $("#from_area_id").append( '<option value="">选择区（县）</option>');
                    $.each(data.list1,function (index,item) {
                        $("#from_area_id").append( '<option value="'+item.id+'">'+item.name+'</option>');
                    });
                }else{
                    $("#from_city_id option").remove();
                    $('#from_area_id option').remove();
                    $("#from_city_id").append( '<option value="">选择城市</option>');
                    $.each(data.list1,function (index,item) {
                        $("#from_city_id").append( '<option value="'+item.id+'">'+item.name+'</option>');
                    });
                    $("#from_area_id").append( '<option value="">选择区（县）</option>');
                    $.each(data.list2,function (index,item) {
                        $("#from_area_id").append( '<option value="'+item.id+'">'+item.name+'</option>');
                    });
                }

            }
        })
    });

html：

            <select name="from_prov_id" id="from_prov_id" class="select">
                <option value="">选择省份</option>
                    <option value="id">北京</option>
                    <option value="id">上海</option>
                   <option value="id">浙江</option>
                    <option value="id">四川</option>
                    <option value="id">山西</option>
                    <option value="id">江苏</option>
                {/volist}
            </select>
            <select name="from_city_id" id="from_city_id" class="select">
                <option value="">选择城市</option>
            </select>
      
            <select name="from_area_id" id="from_area_id" class="select">
                <option value="">选择区县</option>
            </select>

php：

   public function area(){
        $area = new Area();
        $id = input('id');
        $list = $area->getList(['pid'=>$id]);
        $list2 =  $area->getList(['pid'=>$list[0]['id']]);
        return json_encode(['list1'=>$list,'list2'=>$list2]);
    }