Result Size: 625 x 664
x
 
<!DOCTYPE html>
<html>
<body>
<iframe id="myFrame" src="/default.asp" height="200" width="250"></iframe>
<p>Click the button to display the height of the iframe.</p>
<button onclick="myFunction()">Try it</button>
<p id="demo"></p>
<script>
function myFunction() {
  var x = document.getElementById("myFrame").height;
  document.getElementById("demo").innerHTML = x;
}
</script>
</body>
</html>