$(function() {
  var centerAbsolute = function () {
    $('.absolute-center').css({
      position:'absolute',
      left: ($(window).width() - $('.absolute-center').outerWidth())/2,
      top: ($(window).height() - $('.absolute-center').outerHeight())/2
    });
  }
  
  centerAbsolute();
  centerAbsolute();
});