<button id="load">Load It!</button>
<div class="modal js-loading-bar">
 <div class="modal-dialog">
   <div class="modal-content">
     <div class="modal-body">
       <div class="progress progress-popup">
        <div class="progress-bar"></div>
       </div>
     </div>
   </div>
 </div>
</div>

.progress-bar.animate {
   width: 100%;
}

// Setup
this.$('.js-loading-bar').modal({
  backdrop: 'static',
  show: false
});

$('#load').click(function() {
  var $modal = $('.js-loading-bar'),
      $bar = $modal.find('.progress-bar');
  
  $modal.modal('show');
  $bar.addClass('animate');

  setTimeout(function() {
    $bar.removeClass('animate');
    $modal.modal('hide');
  }, 1500);
});