معین

$('#myModal').on('shown.bs.modal', function () {
  $('#myInput').trigger('focus')
})

<div class="modal" tabindex="-1">
  <div class="modal-dialog">
    <div class="modal-content">
      <div class="modal-header">
        <h5 class="modal-title">Modal title</h5>
        <button type="button" class="close" data-dismiss="modal" aria-label="Close">
          <span aria-hidden="true">&times;</span>
        </button>
      </div>
      <div class="modal-body">
        <p>Modal body text goes here.</p>
      </div>
      <div class="modal-footer">
        <button type="button" class="btn btn-secondary" data-dismiss="modal">Close</button>
        <button type="button" class="btn btn-primary">Save changes</button>
      </div>
    </div>
  </div>
</div>

<!-- Button trigger modal -->
<button type="button" class="btn btn-primary" data-toggle="modal" data-target="#exampleModal">
  Launch demo modal
</button>

<!-- Modal -->
<div class="modal fade" id="exampleModal" tabindex="-1" aria-labelledby="exampleModalLabel" aria-hidden="true">
  <div class="modal-dialog">
    <div class="modal-content">
      <div class="modal-header">
        <h5 class="modal-title" id="exampleModalLabel">Modal title</h5>
        <button type="button" class="close" data-dismiss="modal" aria-label="Close">
          <span aria-hidden="true">&times;</span>
        </button>
      </div>
      <div class="modal-body">
        ...
      </div>
      <div class="modal-footer">
        <button type="button" class="btn btn-secondary" data-dismiss="modal">Close</button>
        <button type="button" class="btn btn-primary">Save changes</button>
      </div>
    </div>
  </div>
</div>

<!-- Button trigger modal -->
<button type="button" class="btn btn-primary" data-toggle="modal" data-target="#staticBackdrop">
  Launch static backdrop modal
</button>

<!-- Modal -->
<div class="modal fade" id="staticBackdrop" data-backdrop="static" data-keyboard="false" tabindex="-1" aria-labelledby="staticBackdropLabel" aria-hidden="true">
  <div class="modal-dialog">
    <div class="modal-content">
      <div class="modal-header">
        <h5 class="modal-title" id="staticBackdropLabel">Modal title</h5>
        <button type="button" class="close" data-dismiss="modal" aria-label="Close">
          <span aria-hidden="true">&times;</span>
        </button>
      </div>
      <div class="modal-body">
        ...
      </div>
      <div class="modal-footer">
        <button type="button" class="btn btn-secondary" data-dismiss="modal">Close</button>
        <button type="button" class="btn btn-primary">Understood</button>
      </div>
    </div>
  </div>
</div>

<!-- Scrollable modal -->
<div class="modal-dialog modal-dialog-scrollable">
  ...
</div>

<!-- Vertically centered modal -->
<div class="modal-dialog modal-dialog-centered">
  ...
</div>

<!-- Vertically centered scrollable modal -->
<div class="modal-dialog modal-dialog-centered modal-dialog-scrollable">
  ...
</div>

<div class="modal-body">
  <h5>Popover in a modal</h5>
  <p>This <a href="#" role="button" class="btn btn-secondary popover-test" title="Popover title" data-content="Popover body content is set in this attribute.">button</a> triggers a popover on click.</p>
  <hr>
  <h5>Tooltips in a modal</h5>
  <p><a href="#" class="tooltip-test" title="Tooltip">This link</a> and <a href="#" class="tooltip-test" title="Tooltip">that link</a> have tooltips on hover.</p>
</div>

<div class="modal-body">
  <div class="container-fluid">
    <div class="row">
      <div class="col-md-4">.col-md-4</div>
      <div class="col-md-4 ml-auto">.col-md-4 .ml-auto</div>
    </div>
    <div class="row">
      <div class="col-md-3 ml-auto">.col-md-3 .ml-auto</div>
      <div class="col-md-2 ml-auto">.col-md-2 .ml-auto</div>
    </div>
    <div class="row">
      <div class="col-md-6 ml-auto">.col-md-6 .ml-auto</div>
    </div>
    <div class="row">
      <div class="col-sm-9">
        Level 1: .col-sm-9
        <div class="row">
          <div class="col-8 col-sm-6">
            Level 2: .col-8 .col-sm-6
          </div>
          <div class="col-4 col-sm-6">
            Level 2: .col-4 .col-sm-6
          </div>
        </div>
      </div>
    </div>
  </div>
</div>

<button type="button" class="btn btn-primary" data-toggle="modal" data-target="#exampleModal" data-whatever="@mdo">Open modal for @mdo</button>
<button type="button" class="btn btn-primary" data-toggle="modal" data-target="#exampleModal" data-whatever="@fat">Open modal for @fat</button>
<button type="button" class="btn btn-primary" data-toggle="modal" data-target="#exampleModal" data-whatever="@getbootstrap">Open modal for @getbootstrap</button>

<div class="modal fade" id="exampleModal" tabindex="-1" aria-labelledby="exampleModalLabel" aria-hidden="true">
  <div class="modal-dialog">
    <div class="modal-content">
      <div class="modal-header">
        <h5 class="modal-title" id="exampleModalLabel">New message</h5>
        <button type="button" class="close" data-dismiss="modal" aria-label="Close">
          <span aria-hidden="true">&times;</span>
        </button>
      </div>
      <div class="modal-body">
        <form>
          <div class="form-group">
            <label for="recipient-name" class="col-form-label">Recipient:</label>
            <input type="text" class="form-control" id="recipient-name">
          </div>
          <div class="form-group">
            <label for="message-text" class="col-form-label">Message:</label>
            <textarea class="form-control" id="message-text"></textarea>
          </div>
        </form>
      </div>
      <div class="modal-footer">
        <button type="button" class="btn btn-secondary" data-dismiss="modal">Close</button>
        <button type="button" class="btn btn-primary">Send message</button>
      </div>
    </div>
  </div>
</div>

$('#exampleModal').on('show.bs.modal', function (event) {
  var button = $(event.relatedTarget) // Button that triggered the modal
  var recipient = button.data('whatever') // Extract info from data-* attributes
  // If necessary, you could initiate an AJAX request here (and then do the updating in a callback).
  // Update the modal's content. We'll use jQuery here, but you could use a data binding library or other methods instead.
  var modal = $(this)
  modal.find('.modal-title').text('New message to ' + recipient)
  modal.find('.modal-body input').val(recipient)
})

<div class="modal" tabindex="-1" aria-labelledby="..." aria-hidden="true">
  ...
</div>

<div class="modal-dialog modal-xl">...</div>
<div class="modal-dialog modal-lg">...</div>
<div class="modal-dialog modal-sm">...</div>

<button type="button" data-toggle="modal" data-target="#myModal">Launch modal</button>

$('#myModal').modal(options)

$('#myModal').modal({
  keyboard: false
})

$('#myModal').modal('toggle')

$('#myModal').modal('show')

$('#myModal').modal('hide')

$('#myModal').modal('handleUpdate')

$('#myModal').on('hidden.bs.modal', function (event) {
  // do something...
})