<!DOCTYPE html>
<html>
<body>

<iframe id="myFrame" src="../default.html" height="200" width="250"></iframe>

<p>Click the button to change the height and width of the iframe to 400px.</p>

<button onclick="myFunction()">Try it</button>

<script>
function myFunction() {
    document.getElementById("myFrame").height = "400";
    document.getElementById("myFrame").width = "400";
}
</script>

</body>
</html>