querySelector를 활용한 데이터 참조
document.querySelector('#선택자')
document.querySelector('태그선택자')
document.querySelector('.클래스선택자')
<!DOCTYPE html>
<html lang="en">
<head>
<title>D-day</title>
<script>
const dateFormMaker = function(){
console.log(document.querySelector('#target-year-input'))
};
</script>
</head>
<body>
<input id="target-year-input" class="target-input"/>
<button onclick="dateFormMaker()">버튼</button>
</body>
</html>
실행결과
document.querySelector('#target-year-input')
<실행결과> 해당 태그까지만 가져온다.
<input id="target-year-input" class="target-input">
document.querySelector('#target-year-input').value
2022를 입력하고 버튼을 클릭하면
<실행결과>
2022