Как рассчитать no_of_days между указателями даты в Laravel onchange

Question

У меня есть этот Laravel -5.8 код:

Контроллер

public function store(StoreLeaveRequestRequest $request)
{
    if (! Gate::allows('leave_request_create')) {
        return abort(401);
    }
try {   
        $commencementDate   = Carbon::parse($request->commencement_date);
        $resumptionDate     = Carbon::parse($request->resumption_date);
        $leaverequest = HrLeaveRequest::create([
            'leave_type_id'             => $request->leave_type_id,
            'commencement_date'         => $commencementDate,
            'resumption_date'           => $resumptionDate,               
        ]);
        Session::flash('success', 'Leave Request is created successfully');
        return redirect()->route('service.leave_requests.index');
    } 
    catch (Exception $exception) 
    {
        Session::flash('error', 'Action failed!');
        return redirect()->route('service.leave_requests.index');  
    }        
}

Также у меня есть этот код create.blade

          <div class="col-sm-4">
            <div class="form-group">
                <label>Commencement Date:<span style="color:red;">*</span></label>
                <input type="date" class="form-control" placeholder="dd/mm/yyyy" name="commencement_date" value="{{old('commencement_date')}}"  min="{{Carbon\Carbon::now()->firstOfYear()->format('Y-m-d')}}" max="{{Carbon\Carbon::now()->lastOfYear()->format('Y-m-d')}}">
            </div>
          </div>                    
          <div class="col-sm-4">
            <div class="form-group">
                <label>Resumption Date:<span style="color:red;">*</span></label>
                <input type="date" class="form-control" placeholder="dd/mm/yyyy" name="resumption_date" value="{{old('resumption_date')}}"  min="{{Carbon\Carbon::now()->firstOfYear()->format('Y-m-d')}}" max="{{Carbon\Carbon::now()->lastOfYear()->format('Y-m-d')}}">
            </div>
          </div> 
          <div class="col-sm-4">
            <div class="form-group">
                <label>Requested Days:</label>
                <input  type="number" name="no_of_days" class="form-control" value="{{old('no_of_days')}}" style="width: 100%;" disabled>
            </div>
          </div>   

Javascript

<script type="text/javascript">
    $(document).ready(function() {
        $(function () {
            $('#commencement_date').datetimepicker({
                format: "YYYY-MM-DD"
            });
            $('#resumption_date').datetimepicker({
                format: "YYYY-MM-DD"
            });
        });
    });
</script>

Чего я хочу добиться, так это того, что onchange в resuration_date я хочу вычесть

commencement_date из resuration_date и загрузить результат в no_of_days