<!DOCTYPE html>
<html>
<head>
<title>Login Form</title>
</head>
<body>
<form method="post" action="<?php echo $_SERVER['PHP_SELF']; ?>">
<input type="text" name="username" placeholder="Username" />
<input type="password" name="password" placeholder="Password" />
<input type="submit" value="Login" />
</form>
<?php
if(isset($_POST['username']) && isset($_POST['password'])) {
/* Associative Array with md5 encrypted password */
$loginfo = array("geek12" => md5("1234"), "abc4" => md5("abcd"), "jcb84" => md5("msk53"));
/* Trim whitespace from the beginning and end */
/* Compare with regular expression */
if((trim($_POST['username']) == '') || (ereg ('[^a-zA-Z0-9]', $_POST['username'])))
echo "Invalid username...Usernames only contain letters and digits.";
else {
if((trim ($_POST['password']) == '') || (ereg ('[^[:alnum:][:punct:][:space:]]', $_POST['password'])))
echo "Invalid password...Passwords only contain letters, digits, punctuation and spaces.";
else {
/* Checking username exist or not */
if(isset($loginfo[$_POST['username']])) {
/* Checking password associated with matched username */
if($loginfo[$_POST['username']] == md5($_POST['password'])) {
/* Set session */
session_start();
$_SESSION["user_id"] = $_POST['username'];
echo "Authenticated!";
}
else
echo "Password didn't match!";
}
else
echo "Username didn't match!";
}
}
}
?>
</body>
</html>
/****** Output ******/
Input:
username = geek12
password = 1234
Authenticated!