bootstrap modal center

gistfile1.js

  var setCenterModal = function () {
      $(this).css('display', 'block');
      var $dialog = $(this).find(".modal-dialog");
      var offset = ($(window).height() - $dialog.height()) / 2;
      $dialog.css("margin-top", offset);
  };
  
  $('.modal').on('show.bs.modal', setCenterModal);
  
  $(window).on("resize", function () {
      $('.modal:visible').each(setCenterModal);
  });