Bootstrap 3 - Centering Modal Popup

by Kushal Jayswal

HTML

<link rel="stylesheet" href="//maxcdn.bootstrapcdn.com/bootstrap/3.2.0/css/bootstrap.min.css">
<script src="//maxcdn.bootstrapcdn.com/bootstrap/3.2.0/js/bootstrap.min.js"></script>
<!-- Button trigger modal -->
<button class="btn btn-primary btn-lg" data-toggle="modal" data-target="#myModal">Launch demo modal</button>
<!-- Modal -->
<div class="modal fade" id="myModal" tabindex="-1" role="dialog" aria-labelledby="myModalLabel" aria-hidden="true">
  <div class="vertical-alignment-helper">
    <div class="modal-dialog vertical-align-center">
      <div class="modal-content">
        <div class="modal-header">
          <button type="button" class="close" data-dismiss="modal"><span aria-hidden="true">&times;</span><span class="sr-only">Close</span>

          </button>
          <h4 class="modal-title" id="myModalLabel">Modal title</h4>

        </div>
        <div class="modal-body">...</div>
        <div class="modal-footer">
          <button type="button" class="btn btn-default" data-dismiss="modal">Close</button>
          <button type="button" class="btn btn-primary">Save changes</button>
        </div>
      </div>
    </div>
  </div>
</div>

CSS

.modal {}

.vertical-alignment-helper {
  display: table;
  height: 100%;
  width: 100%;
}

.vertical-align-center {
  /* To center vertically */
  display: table-cell;
  vertical-align: middle;
}

.modal-content {
  /* Bootstrap sets the size of the modal in the modal-dialog class, we need to inherit it */
  width: inherit;
  height: inherit;
  /* To center horizontally */
  margin: 0 auto;
}