二级联动

例子：

<div class="title"><span>5、审批人部门</span><img src="{{url('signet/img/star.png')}}" alt="" /></div>
        <div class="partment">
            <select id="applicantion_department_id2" name="applicantion_department_id2" style="width: 100%"  >
                <option value="aa" >请选择部门</option>
                @if(!empty($department))
                    @foreach($department as $v )
                        <option value="{{$v['depart_id']}}" >{{$v['depart_name']}}</option>
                    @endforeach
                @endif
            </select>
        </div>
        <div class="title"><span>审批人</span><img src="{{url('signet/img/star.png')}}" alt="" /></div>
        <div class="partment">
            <select id="depart_audit_u_id" name="depart_audit_u_id" style="width: 100%" >
                <option  value="aa"  >请选择审批人</option>
                @if(!empty($user))
                    @foreach($user as $v )
                        <option value="{{$v['id']}}" >{{$v['name']}}</option>
                    @endforeach
                @endif
            </select>
        </div>

<script>
    //审核人二级联动
    $(function(){
        $("#applicantion_department_id2").change(function(){
            var data = $("#applicantion_department_id2").serialize();
            data = data +"&_token={{csrf_token()}}";
            $.ajax({
                url:"/admin/user/aggregation2", //你的路由地址
                type:"post",
                dataType:"json",
                data:data,
                timeout:30000,
                success:function(data){
                    $("#depart_audit_u_id").empty();
                    var count = data.length;
                    var i = 0;
                    var b="<option  value='aa' >请选择审批人</option>";
                    for(i=0;i<count;i++){
                        b+="<option value='"+data[i].id+"'>"+data[i].name+"</option>";
                    }
                    $("#depart_audit_u_id").append(b);

                }
            });
        });
    })
</script>

后台：

/**
     * 审核人部门、用户二级联动
     * @author:chenbing
     * @date:2018-3-13
     */
    public function aggregation2(Request $request)
    {
        $ary_request = $request->input();

        $users=WxUser::where("department",$ary_request['applicantion_department_id2'])->get()->toArray(); //该部门下的所有人
        echo json_encode($users);
    }