<!DOCTYPE html>
<html>
<body>
<div id="myDIV">
<p id="demo">This is a p element with id="demo" in a div.</p>
</div>
<p>Click the button to change the text of the p element in div.</p>
<button onclick="myFunction()">Try it</button>
<script>
function myFunction() {
var x = document.getElementById("myDIV");
x.querySelector("#demo").innerHTML = "Hello World!";
}
</script>
</body>
</html>