ㅇ

<!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>
    <link rel="stylesheet" href="style.css">
</head>
<body>
    <div class="text-js">안녕</div>
    <form>
        <input type="button" id="btn-js" value="짜잔">
    </form>
<script src="main.js"></script>    
</body>
</html>


차례대로 html css js 인데. 버튼을 눌르면  changetext 함수가 실행되면서 병신아가 안녕 앞에 출력되게 만들고싶은데 뭐가 문제인지 알려줭 ㅠㅠ

.change-js::before{
    content:"병신아";
}


const button = document.querySelector('btn-js');
const text = document.querySelector('text-js');

button.addEventListener('click' , changetext());

function changetext(){
    text.classList.add('change-js::before')
};

function init(){

};
init();