<!DOCTYPE html>
<html>
<body>
<iframe src="http://www.cnn.com"></iframe>
<iframe src="http://www.bbc.com"></iframe>
<iframe src="http://www.nytimes.com"></iframe>
<p>Click the button to get the number of frames found on this page.</p>
<button onclick="myFunction()">Try it</button>
<p id="demo"></p>
<script>
function myFunction() {
var x = window.length;
document.getElementById("demo").innerHTML = x;
}
</script>
</body>
</html>