ch12.html

<!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>
    <script>
      //생성자 함수식 선언방식만 존재함
      var today = new Date();
      document.write(today + '<br>');

      //특정 날짜 선언, 월이 0~11사이의 숫자
      var xmas = new Date(2022, 11, 25);
      document.write(xmas + '<br>');

      document.write(today.toLocaleDateString() + '<br>');
      document.write(today.toLocaleTimeString() + '<br>');

      //년 월 일
      var y = today.getFullYear();
      var m = today.getMonth() + 1;
      var d = today.getDate();
      var day = today.getDay(); // 0~6사이의 인덱스

      var week = ['일', '월', '화', '수', '목', '금', '토'];
      if (m < 10) {
        m = '0' + m;
      }
      if (d < 10) {
        d = '0' + d;
      }

      document.write(
        y + '년 ' + m + '월 ' + d + '일 ' + week[day] + '요일<br>'
      );

      //시 분 초
      var h = today.getHours();
      var m2 = today.getMinutes();
      var s = today.getSeconds();
      document.write(h + '시 ' + m2 + '분 ' + s + '초<br>');

      today.setDate(d + 99);
      document.write(today.toLocaleDateString() + '<br>');

      //------
      var ySelect = '<select>';

      for (var i = y; i >= 1900; i--) {
        ySelect += '<option>' + i + '년</option>';
      }

      ySelect += '</select>';
      document.write(ySelect);
    </script>
  </head>
  <body></body>
</html>