<html>
<body>
<iframe id="myFrame" src="/default.asp" height="200" width="250"></iframe>
<p>Click the button to change the height of the iframe to 400px.</p>
<button onclick="myFunction()">Try it</button>
<script>
function myFunction() {
document.getElementById("myFrame").height = "400";
}
</script>
</body>
</html>