<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>Document</title>
</head>
<body>
<p id="target">Hello world</p>
<script>
const target = document.getElementById("target");
// attribute 방식
target.setAttribute("class", "important");
// property 방식
target.className = "important";
</script>
</body>
</html>
Backend Engineer