// Connect to database $db = mysqli_connect('localhost', 'username', 'password', 'database'); // Sanitize user input $username = mysqli_real_escape_string($db, $_POST['username']); $password = mysqli_real_escape_string($db, $_POST['password']); // Query database using sanitized input $query = "SELECT * FROM users WHERE username='$username' AND password='$password'"; $result = mysqli_query($db, $query);
// Validate phone number $phone = "(123) 456-7890"; $pattern = "/^\(\d{3}\) \d{3}-\d{4}$/"; if (preg_match($pattern, $phone)) { echo "Valid phone number!"; } else { echo "Invalid phone number."; }