modalPrint.html

 <!-- Modal -->
  
  <div id="modalPrint" class="modal fade" role="dialog">
  <div class="modal-dialog">

    <!-- Modal content-->
    <div class="modal-content">
      <div class="modal-header">
        <button type="button" class="close" data-dismiss="modal">&times;</button>
        <h4 class="modal-title">Seleziona intervallo di stampa</h4>
      </div>
      <div class="modal-body">    
          <form>
          <div class="form-group">
               <div class="form-group">
                       <label>Indicare la data d'invio</label>
                          <div class='input-group date col-sm-3' id='dataInvio' data-date-format="DD/MM/YYYY">
                            <input type='text' class="form-control" required >
                            <span class="input-group-addon">
                                <span class="glyphicon glyphicon-calendar"></span>
                            </span>
                          </div>
                          <div class="help-block with-errors"></div>
                    </div>
               <button type="submit" id="print" class="btn btn-default btn-sm pull-right" data-dismiss="modal">
                                        <span class="glyphicon glyphicon-print"></span>
                                        <span style="font-size:smaller;">Stampa</span>
               </button> 
          </div>
         </form>
            
      <div class="modal-footer">
       
      </div>
    </div>
  </div>
</div>
<script>
    $('#modalPrint').validator().on('submit', function () {
       console.log('ok')
     });
</script>