<?php
    require_once('dbconfig.php');
    session_start();

    $username = stripslashes($_POST['username']);
    $password = stripslashes($_POST['password']);


        $query = "SELECT username FROM `user` WHERE username='$username'";

    $result = mysqli_query($conn,$query);
    $count = mysqli_num_rows($result);
        if($count==1){
                echo "<script>alert('Username already exists')</script>";
        }
        elseif($count==0){
            $query1 = "INSERT INTO `user`(`username`, `password`) VALUES ('$username','$password')";
            $result1 = mysqli_query($conn,$query1);
        if ($result1) {
        header("Location: login.html");
        }
        else{
        header("Location: login.html");
        }
    }
?>