<!DOCTYPE html>
<style>
#target {
  position: absolute;
  width: 100px;
  height: 100px;
  background: blue;
  transform: translate(calc(50vw - 50px), calc(50vh - 50px));
}
</style>
This box should be located in the center of the page.
<div id="target"></div>
<script>
window.resizeTo(window.innerWidth / 2, window.innerHeight / 2);
</script>