<!DOCTYPE html>
<html>
<head>
<style>
div {
border: 1px solid black;
margin: 5px;
}
</style>
</head>
<body>
<div id="myDIV">
<p>First p element in div.</p>
<p>Another p element in div.</p>
<p>A third p element in div.</p>
</div>
<p>Click the button to find out how many p elements there are inside the div element.</p>
<button onclick="myFunction()">Try it</button>
<p id="demo"></p>
<script>
function myFunction() {
var div = document.getElementById("myDIV");
var nodelist = div.getElementsByTagName("P");
document.getElementById("demo").innerHTML = nodelist.length;
}
</script>
</body>
</html>