{position:fixed; top:90px; left:150 px; z-index:9999; overflow:hidden;}

.container {
  display: flex;
  align-items: center;
  justify-content: center;
}

var $box = $('#box');

var bw = $box.width() / 2;
var bh = $box.height() / 2;

var wh = $(window).height() / 2;
var ww = $(window).width() / 2;

$box.css({'left': ww-bw, "top": wh-bh})

function centerObject(selector) {
var x = $(window).height() - $(selector).height();
var y = $(window).width() - $(selector).width();
$(selector).css("left", y / 2).css("top", x / 2);
};

#divX {
    position: fixed;
    left: 50%;
    top: 50%;
    width: 100px;
    height: 100px;
    margin-left: -50px;
    margin-top: -50px;
    background-color: #0000FF;
}

.centered {
  position: fixed;
  top: 50%;
  left: 50%;
  margin-top: -50px;
  margin-left: -100px;
}