如何使绝对定位的元素与另一个元素具有相同的大小

<div id="targetElement">目标元素</div>
<div id="absoluteElement">绝对定位的元素</div>

#targetElement {
  width: 200px;
  height: 100px;
  background-color: #ccc;
}

#absoluteElement {
  position: absolute;
  top: 50px;
  left: 50px;
}

var targetElement = document.getElementById('targetElement');
var absoluteElement = document.getElementById('absoluteElement');

var targetWidth = targetElement.offsetWidth;
var targetHeight = targetElement.offsetHeight;

absoluteElement.style.width = targetWidth + 'px';
absoluteElement.style.height = targetHeight + 'px';