title: How to add on click event in datatables buttons like excel
body: <pre><code>buttons: [
    {
      extend: 'excelHtml5',
      title: 'LicenseDetails_'+(++download_file_counter)+'_'+today,            
      text: 'Excel',
      exportOptions: {
        modifier: {
          page: 'current'                         
        }
      }
    }
  ]
  </code></pre>
  
  <p>On click of excel button download file counter should increment. Please tell me where to add onclick event.</p>