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<!DOCTYPE html>
<html>
<style>
.democlass {color:red}
</style>
<body>
<h1>HTML DOM Elements</h1>
<h2>The setAttribute() Method </h2>
<p>Set the first H1's class attribute to "democlass".</p>
<script>
const element = document.getElementsByTagName("H1")[0];
element.setAttribute("class", "democlass");
</script>
</body>
</html>