please help me. how i can update data from database using select option, ajax onchange without submit.

my view :

{!! Form::model($UserAccess,['method' => 'POST','url'=>['setting/updaterole']]) !!}
                    <table class="dataTable" id="table-user">
                        <thead class="grey lighten-3">
                            <tr>
                                <td class="center-align no-sort">Photo</td>
                                <td class="center-align">Fullname</td>
                                <td class="center-align">Rule</td>
                                <td class="center-align">Action</td>
                            </tr>
                        </thead>
                        <tbody>
                            <?php $hitung = $UserAccess->count(); ?>
                            @foreach($UserAccess as $list)
                            <tr>
                                <td class="center-align" width="50">
                                    @if($list->avatar == NULL)
                                    <img class="circle responsive-img" width="50" src="{{asset(config('param.url_uploads').'blank.jpg')}}"/>
                                    @else
                                    <img class="circle responsive-img" width="50" src="{{$list->avatar}}"/>
                                    @endif
                                </td>
                                <td class="red1-text lato-bold center-align">{{$list->name}}</td>
                                <td class="center-align" width="150">
                                    <select id="selectrole" name="selectrole" data-url="{{url('/setting/updaterole')}}" data-token="{{ csrf_token() }}">
                                        @foreach($UserAccessRole as $listRole)
                                            <option value="{{$listRole->id}}" @if($list->user_access_role_id_fk == $listRole->id) selected="selected"@endif>{{$listRole->name}}</option>
                                        @endforeach
                                    </select>
                                </td>
                                <input type = "hidden" value = "{{$list->id}}" name = "idmain">
                                @if($hitung > 2)
                                    <td class="center-align">
                                        <a href = "remove_access/{{$list->id}}/delete" >Remove Access<a/>
                                    </td>
                                @else
                                    <td class="center-align">Remove Access</td>
                                @endif
                            </tr>
                            @endforeach
                        </tbody>
                    </table>
{!! Form::close() !!}
@section('page-script')
<script type="text/javascript">
$('select').on('change',function(){
var city =  $( "select option:selected" ).val();
var token = $(this).data('token');
var base_url = $(this).data('url');
 $.ajax({
    url:base_url+'/updaterole',
    type: 'POST',
    data: { _token :token,city_id:city_id },
    success:function(msg){
       alert("success");
    }
 });


})
</script>
@endsection

my controller :

public function doUpdateAccessRole($id, Request $request)
{
   $place_id = $request->get('id');
   $Role = UserAccess::findOrFail($id);
   $Role->user_access_role_id_fk = $id_role;
   $Role->update($request->all());
   return 'success';
}

my routes

Route::post('setting/updaterole',['uses'=>'SettingController@doUpdateAccessRole','as'=>'updateaccessrole']);

i don't understand whats wrong with my code. when i change the select option value nothing happen with my program. please help me, thank you.