세션ID :
session1 :
Warning: Undefined array key "session1" in /users/2021/i2151035/public_html/2022/WebProg/ch10/exam10-07.php on line 15

session2 :
Warning: Undefined array key "session2" in /users/2021/i2151035/public_html/2022/WebProg/ch10/exam10-07.php on line 16

session3 :
Warning: Undefined array key "session3" in /users/2021/i2151035/public_html/2022/WebProg/ch10/exam10-07.php on line 17

세션설정
세션확인
세션변수 session1 삭제
세션삭제