When changing the action of a form, does not work in SAFARI?

<link href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css" rel="stylesheet">
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-datepicker/1.8.0/css/bootstrap-datepicker.css" />
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-datepicker/1.8.0/js/bootstrap-datepicker.js"></script>

<form class="" id="formulario" action="https://booking.frontdeskmaster.com/" method="get" onsubmit="submit_function(this)">
  <div class="col-md-3 col-sm-12 col-xs-12">
    <h4 class="pd-bottom text-left">DESTINATION</h4>
    <label>
      <select class="form-control select-padding" name="hostelId" id="hostel" required>
        <option value="" selected="selected" class="">Choose a hostels</option>
        <option value="kVcaDJqn082LE0fJU7Utg3PbpYwWWaYX">Wild Rover Cusco</option>
        <option value="US5sEq+k8frM8OV8XVy3ARy3BnLoHG1I">Wild Rover Arequipa</option>
        <option value="N7ZfctR15fSalY8BR6N1Q9bealzffhYU">Wild Rover La Paz</option>
        <option id="prueb" value="MOtFJG" data-action="https://hotels.cloudbeds.com/reservation/MOtFJG">Wild Rover Huacachina</option>
      </select>
    </label>
  </div>
  <div class="col-md-3 col-sm-12 col-xs-12">
    <h4 class="pd-bottom text-left">Check In</h4>
    <input name="arrival" type="text" class="form-control campo select-padding" size="10" id="datepicker" value="dd/mm/yyyy" readonly style="background: white;" />
  </div>
  <div class="col-md-2 col-sm-6 col-xs-6">
    <h4 class="pd-bottom text-left">N° Nights</h4>
    <label>
      <select name="nights" class="form-control btn-select select-padding">
        <option value="1">1</option>
        <option value="2" selected="">2</option>
        <option value="3">3</option>
        <option value="4">4</option>
        <option value="5">5</option>
        <option value="6">6</option>
        <option value="7">7</option>
        <option value="8">8</option>
        <option value="9">9</option>
        <option value="10">10</option>
        <option value="11">11</option>
        <option value="12">12</option>
        <option value="13">13</option>
        <option value="14">14</option>
        <option value="15">15</option>
        <option value="16">16</option>
        <option value="17">17</option>
        <option value="18">18</option>
        <option value="19">19</option>
        <option value="20">20</option>
        <option value="21">21</option>
        <option value="22">22</option>
        <option value="23">23</option>
        <option value="24">24</option>
        <option value="25">25</option>
        <option value="26">26</option>
        <option value="27">27</option>
        <option value="28">28</option>
        <option value="29">29</option>
        <option value="30">30</option>
      </select>
    </label>
  </div>
  <div class="col-md-2 col-sm-6 col-xs-6">
    <h4 class="pd-bottom text-left">N° Guests</h4>
    <label class="">
      <select name="guests" class="form-control btn-select select-padding">
        <option value="1">1</option>
        <option value="2" selected="">2</option>
        <option value="3" >3</option>
        <option value="4">4</option>
        <option value="5">5</option>
        <option value="6">6</option>
        <option value="7">7</option>
        <option value="8">8</option>
        <option value="9">9</option>
        <option value="10">9+</option>
      </select>
    </label>
  </div>
  <div class="col-md-2 col-sm-12 col-xs-12" id="book-form">
    <input id="enviar" class="submit btn-book" type="submit" value="BOOK NOW" onclick="document.location.reload(true)">
  </div>
</form>




<!-- NOT DELETE, CODE CHANGE THE FORM ACTION -->
<script>
  function submit_function(form) {
    var selected = document.getElementById('hostel');
    var dataset = selected[selected.selectedIndex].dataset;

    if (dataset.action) {
      form.action = dataset.action;
    }
    return true;
  };

</script>
<!-- FIN -->




<script type="text/javascript">
  $(function() {
    $('#datepicker').datepicker({
      dateFormat: 'dd/M/yy',
    });
  });
</script>
<script type="text/javascript">
  $(function() {
    $("#datepicker1").datepicker({
      minDate: 0
    });
  });
</script>