@php
$excelBase = public_path('assets/excelbtncss');
$ev = function ($f) use ($excelBase) {
    $p = $excelBase . '/' . $f;
    return @is_file($p) ? (string) @filemtime($p) : (string) time();
};
@endphp
<link rel="stylesheet" href="{{url('assets/excelbtncss/responsive.bootstrap.min.css')}}?v={{ $ev('responsive.bootstrap.min.css') }}">
<link rel="stylesheet" href="{{url('assets/excelbtncss/buttons.dataTables.min.css')}}?v={{ $ev('buttons.dataTables.min.css') }}">
<script src="{{url('assets/excelbtncss/dataTables.responsive.min.js')}}?v={{ $ev('dataTables.responsive.min.js') }}"></script>
<script src="{{url('assets/excelbtncss/responsive.bootstrap.min.js')}}?v={{ $ev('responsive.bootstrap.min.js') }}"></script>
<script src="{{url('assets/excelbtncss/jszip.min.js')}}?v={{ $ev('jszip.min.js') }}"></script>
<script src="{{url('assets/excelbtncss/dataTables.buttons.min.js')}}?v={{ $ev('dataTables.buttons.min.js') }}"></script>
<script src="{{url('assets/excelbtncss/buttons.html5.min.js')}}?v={{ $ev('buttons.html5.min.js') }}"></script>