Javascript getBoundingClientRect() method returns the relative positioning

Source Code: (back to article)

<!DOCTYPE html>
<html>
  <head>
    <title>Title of the document</title>
    <style>
      #div1 {
        height: 200px;
        width: 300px;
        overflow: auto;
      }
      #myDiv {
        width: 250px;
        height: 150px;
        border: 1px solid red;
      }
      #div2 {
        width: 1000px;
        height: 1000px;
      }
    </style>
  </head>
  <body>
    <div id="div1">
      <div id="myDiv">Use scrollbar to change the position. </div>
      <div id="div2"></div>
    </div>
    <br />
    <button onclick="GetPosition()">Get the location of the item with a red frame!</button>
    <div id="demo"></div>
    <script type="text/javascript">
      function GetPosition() {
        let div = document.getElementById("myDiv");
        let rect = div.getBoundingClientRect();
        x = rect.left;
        y = rect.top;
        width = rect.right - rect.left;
        height = rect.bottom - rect.top;
        document.getElementById("demo").innerHTML = (" Left: " + x + " Top: " + y + " Width: " + width + " Height: " + height);
      }
    </script>
  </body>
</html>