index.php for login - 1

<?php
session_start();
$islogin = false;
if( isset($_SESSION['userid']) ){
	if( $_SESSION['userid'] ) {
		$islogin = true;
	}
}
?>
<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>Member</title>
</head>
<body>
	<div>
		<?php if( ! $islogin ): ?>
		<form action="login.php" method="POST">
			<label for="userid">아이디</label>
			<input type="text" id="userid" name="userid" placeholder="your id...">
			<label for="userpw">비밀번호</label>
			<input type="password" id="userpw" name="userpw">
			<button type="submit">로그인</button>
		</form>
		<form action="join.php" method="POST">
			<h1>회원가입</h1>
			<label for="uid">아이디</label>
			<input type="text" id="uid" name="uid"><br>
			<label for="uname">이름</label>
			<input type="text" id="uname" name="uname"><br>
			<label for="upw">비밀번호</label>
			<input type="password" id="upw" name="upw"><br>
			<button type="text">가입하기</button>
		</form>
	<?php else: ?>
		<form action="logout.php" method="GET">
			<?php echo $_SESSION['userid'];?>
			<?php echo $_SESSION['username'];?>
			<button type="submit">로그아웃</button>
		</form>
	<?php endif ?>
	</div>
</body>
</html>