Untitled

<?php
	session_start();


	$connect = mysql_connect('localhost', '', '') or die (mysql_error());
	mysql_select_db('dopdb');

		if(isset($_POST['submit'])){
			$username = $_POST['username'];
			$login = $_POST['login'];
			$password = $_POST['password'];
			$r_password = $_POST['r_password'];
			if($password == $r_password){
				$password = md5($password);
				$query = mysql_query("INSERT INTO users VALUES ('','$username','$login','$password')") or die (mysql_error());
			}
			else{
				die("Passwords doesn't match.");
			}
		}
		if(isset($_POST['enter'])){
			$e_login = $_POST['e_login'];
			$e_password = md5($_POST['e_password']);

			$query = mysql_query("SELECT '' FROM users WHERE login = $e_login");
			$user_data = mysql_fetch_array($query);


			if($user_data['password'] == $e_password){
				session_start();
				$_SESSION['your_session'] = $e_login;
				}
				else{
					echo 'Wrong password!';
			}
		}
			if(isset($_POST['logout'])){
				unset($_SESSION['your_session']);
				session_destroy();
		}
?>

<!doctype html>
<html lang="ru">
<head>
<title>PHP&MySQL</title>
	<meta charset="windows-1251">
	<link rel="stylesheet" type="text/css" href="style.css" />
</head>
<body id="body">
		<div id="header">
			<span id="greet">Test Site</span>
				<span class="urls">
					<a href="index.php" >Главная</a>
					<a href="page1.php" >Страница 1</a>
					<a href="page2.php" >Страница 2</a>
					<a href="registration.php">Регистрация</a>
				</span>
		</div>
<?php
		if(isset($_SESSION['your_session'])){
			$login_check = true;
			echo '<p style = "font-size:36, color: blue;" >Добро пожаловать!</p><br>
			<form method="post" action="index.php">
			<input class="submit" type="submit" name="logout" value="Выйти">
			</form>
			';
		}
		else{
			echo '<form id="login_form" action="/" method="post">
				<label>Логин</label><br>
				<input class="form_input" type="text" name="e_login" required /><br>
				<label>Пароль</label><br>
				<input class="form_input" type="password" name="e_password" required /><br>
				<input class="submit" type="submit" name="enter" value="Отправить"/>
		</form>';
		}

?>
</body>
<footer id="footer">
		<b id="basement">Footer</b>
</footer>
</html>