※ addClass() 사용
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.min.js"></script>
<script>
$(document).ready(function(){
$("button").click(function(){
$("h1, h2, p").addClass("blue");
$("div").addClass("important");
});
});
</script>
</head>
<body>
<h1>Heading 1</h1>
<h2>Heading 2</h2>
<p>This is a paragraph.</p>
<p>This is another paragraph.</p>
<div>This is some important text!</div><br>
<button>Add classes to elements</button>
</body>
</html>
※ 실행화면
실행화면(class 속성이적용) - 클릭하시면 자세히 볼 수 있습니다.