jq三级联动

test.html　　　　　　　　　　　
　　　　
　　　　　　　　　　<div class="a_list">
                    <div class="a_title">商城分类：</div>
                    <div class="a_i">*</div>
                    <select style="margin-left: 20px" id="s_fenlei" name="s_fenlei" class="a_bendian">
                        <option value="">-请选择-</option>
                        {volist name='s_fenlei' id='s_fenlei'}
                        <option value="{$s_fenlei.id}">{$s_fenlei.name}</option>
                        {/volist}
                    </select>
                    <select id="s_fenlei1" name="s_fenlei1" class="a_bendian">
                        <option>-请选择-</option>
                    </select>
                    <select id="s_fenlei2" name="s_fenlei2" class="a_bendian">
                        <option>-请选择-</option>
                    </select>
                </div>

test.js
//商城分类三级联动
        $("#s_fenlei").change(function () {

            var fenlei = $('#s_fenlei').val();
            if(fenlei==""){
                $("#pinpai").hide();
            }else{
                $("#pinpai").show();
            }
            var list = '<option value="">-请选择-</option>';
            var list1 = '<option value="">-请选择-</option>';
            $.ajax({
                url:"{:url('sgetfenlei')}",
                data:{b_fen:fenlei},
                type:'POST',
                datatype:'TEXT',
                success:function (d) {
                    //组成二级分类的select
                    if(d.data.pinpai.length==0){

                        $("#s_fenlei1").hide();
                        return false;
                    }else {
                        $("#s_fenlei1").show();
                        for(var i=0;i<d.data.fenlei2.length;i++){
                            list1 = list1+"<option value='"+d.data.fenlei2[i].id+"'>"+d.data.fenlei2[i].name+"</option>";
                        }
                        $("#s_fenlei1").html(list1);

                    }
                    //组成品牌的select
                    if(d.data.pinpai.length==0){

                        $("#pinpai").hide();
                        return false;
                    }
                    for(var i=0;i<d.data.pinpai.length;i++){
                        list = list+"<option value='"+d.data.pinpai[i].brand_id+"'>"+d.data.pinpai[i].name+"</option>";
                    }
                    $("#brand").html(list);
                }
            });
        });
        $("#s_fenlei1").change(function () {
            var fenlei = $('#s_fenlei1').val();
            var list1 = '<option value="">-请选择-</option>';
            $.ajax({
                url:"{:url('sgetfenlei')}",
                data:{b_fen:fenlei},
                type:'POST',
                datatype:'TEXT',
                success:function (d) {
                    console.log(d);
                    if(d.data.pinpai.length==0){

                        $("#s_fenlei2").hide();
                        return false;
                    }else {
                        $("#s_fenlei2").show();
                        for(var i=0;i<d.data.fenlei2.length;i++){
                            list1 = list1+"<option value='"+d.data.fenlei2[i].id+"'>"+d.data.fenlei2[i].name+"</option>";
                        }
                        $("#s_fenlei2").html(list1);

                    }
                }
            });
        });