I have a booking form and I need just two input #checkin and #checkout and that is why I have used datepicker with daterange everything is going ok almost one thing is how can I choose just 15 day between two date ?
by the way I'm using Pikaday datepicker
$(document).ready(function() {
  $('.flexdatalist').flexdatalist({
    minLength: 0,
    searchContain: true,
  }).on('select:flexdatalist', function() {
    $('#checkin').trigger("click");
  });
  assignPicker = function(id, whenClosed) {
    if (typeof whenClosed !== 'function') {
      whenClosed = null;
    }
    return new Pikaday({
      numberOfMonths: 2,
      field: document.getElementById(id),
      format: "DD.MM.YYYY",
      minDate: new Date(),
      firstDay: 1,
      maxDate: new Date(2020, 12, 31),
      onSelect: function() {
        e = this.getDate();
      },
      onSelect: whenClosed
    });
  }
  assignPicker('checkin', function() {
    $('#checkout').trigger("click");
  });
  assignPicker('checkout', function() {
    $('#select').trigger("click");
  });
});
 body {
            padding: 30px;
        }
        input,
        select {
            width: 100%;
            padding: 10px;
            border: 1px solid #ccc;
        }
  <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous">
  <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/pikaday/1.5.1/css/pikaday.min.css" />
  <link rel="stylesheet" href="https://cdn.anitur.com.tr/example/flexdatalist/flexdatalist.css" />
  <div class="container">
    <div class="row">
      <div class="col-lg-3 col-md-3 col-sm-3">
        <input type="text" name="" class='flexdatalist' data-min-length='1' list='languages' name='language' />
        <datalist id="languages">
          <option value="PHP">PHP</option>
          <option value="JavaScript">JavaScript</option>
          <option value="Cobol">Cobol</option>
          <option value="C#">C#</option>
          <option value="C++">C++</option>
          <option value="Java">Java</option>
          <option value="Pascal">Pascal</option>
          <option value="FORTRAN">FORTRAN</option>
          <option value="Lisp">Lisp</option>
          <option value="Swift">Swift</option>
          <option value="ActionScript">ActionScript</option>
        </datalist>
      </div>
      <div class="col-lg-3 col-md-3 col-sm-3">
          <input type="text" id="checkin" />
      </div>
      <div class="col-lg-3 col-md-3 col-sm-3">
          <input type="text"  id="checkout" />
      </div>
      <div class="col-lg-3 col-md-3 col-sm-3">
<form action="" method="get">
        <select name="select" id="select">
          <option value="0">Choose</option>
          <option value="1">1</option>
          <option value="2">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>
        </select>
      </form>
      </div>
    </div>
  </div>
  <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script>
  <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js" integrity="sha384-Tc5IQib027qvyjSMfHjOMaLkfuWVxZxUPnCJA7l2mCWNIpG9mGCD8wGNIcPD7Txa" crossorigin="anonymous"></script>
  
    <script src="https://cdnjs.cloudflare.com/ajax/libs/pikaday/1.5.1/pikaday.min.js"></script>
  <script src="https://cdn.anitur.com.tr/example/flexdatalist/flexdatalist.js"></script>
if you can check it out on codepen instead of stackoverflow snippet