세션 ID : hu8dmiq6sp6tv5torjmbod1viu
session1 :
Warning: Undefined array key "session1" in /users/2018/i1858020/public_html/2019/webprog/ch10/exam10-08.php on line 13

session2 :
Warning: Undefined array key "session2" in /users/2018/i1858020/public_html/2019/webprog/ch10/exam10-08.php on line 14

session3 :
Warning: Undefined array key "session3" in /users/2018/i1858020/public_html/2019/webprog/ch10/exam10-08.php on line 15

세션 설정
세션 확인
세션 변수 session1 삭제
모든 세션 변수 삭제