Try this one
<!doctype html>
<html>
<head>
<title>Modify HTML Element in JS</title>
</head>
<body>
<h1 id="heading">This is a heading</h1>
<p>Then comes a paragraph or a bunch of paragraphs.</p>
<p>So let's add another paragraph.</p>
<div class="parentDiv">
<div class="childDiv">Hello JS!</div>
<div class="childDiv">Hello JS again!</div>
</div>
<hr/>
<script>
// change heading text
document.getElementById("heading").innerText="My Webpage";
// change HTML code inside childDiv element
document.getElementsByClassName("childDiv")[1].innerHTML="<b>I am learning JS</b>";
</script>
</body>
</html>
