<?php
    require_once 'conn.php';

    if(ISSET($_POST['save'])){
        if(!empty($_POST['firstname']) && !empty($_POST['lastname']) && !empty($_POST['city']) && !empty($_POST['postal_code'])){
            $firstname = $_POST['firstname'];
            $lastname = $_POST['lastname'];
            $city = $_POST['city'];
            $postal_code = $_POST['postal_code'];

            $conn->query("INSERT INTO `member` VALUES('', '$firstname', '$lastname', '$city', '$postal_code')") or die(mysqli_errno());

            header('location: index.php');

        }else{
            echo "<script>alert('Please complete the required field!')</script>";
        }
    }
?>