Verifikasi Email OTP menggunakan PHP di Server Langsung

<!DOCTYPE html>

<html lang="en">

<?php

    session_start();

    $otp=$_SESSION["OTP"];

    if(isset($_SESSION["logged-in"])){

        header("Location:profile.php");

    }

    $username="sign up";

    $login_btn="Login";

    if(isset($_SESSION["username"])){

        $username=$_SESSION["username"];

        $login_btn="Logout";

    }

    if($_SERVER["REQUEST_METHOD"]=="POST"){

        $con=mysqli_connect('localhost',

            'database_username',

            'database_pass','database_name');

        if(!$con)

            echo ("failed to connect to database");

        $username1=$_POST['username'];

        $prefix="_";

        $username=$prefix.$username1;

        $password=$_POST['Password'];

        $repassword=$_POST['RePassword'];

        $email1=$_POST['Email'];

        $email=strval($email1);

        if($password!=$repassword){

            echo("<script>alert('password not matches')</script>");

        }

        else{

            if(strlen($password)<8){

                echo(

    "<script>alert('password length must be atleast 8')</script>");

            }

            else{

                $query="insert into 1_user(username,email,password)

                        values('$username','$email','$password')";

                $sql = "SELECT id,username, password FROM 1_user";

                $result = $con->query($sql);

                $username_already_exist=false;

                $email_already_exist=false;

                

                if(($result->num_rows)> 0){

                    while($row = $result->fetch_assoc()) {

                        

                            " - username= " . $row["username"] .

                            " password= " . $row["password"] . "<br>";

                        if($row["username"]==$username){   

                            $username_already_exist=true;

                            break;

                        }

                        if($row["email"]==$email){   

                            $email_already_exist=true;

                            break;

                        }

                    }

                }

                

                if($username_already_exist==false){

                    

                    $from ="support@libraryatcoer.tk";

                    $to=$email;

                    $subject="verify-account-otp";

                    

                    $otp=rand(100000,999999);

                    $message=strval($otp);

                    $headers="From:" .$from;

                    if(mail($to,$subject,$message,$headers)){

                        $_SESSION["username"]=$username;

                        $_SESSION["OTP"]=$otp;

                        $_SESSION["Email"]=$email;

                        $_SESSION["Password"]=$password;

                        $_SESSION["registration-going-on"]="1";

                        header("Location:verify-otp.php");

                    }

                    else

                        echo("mail send faild");

                }

                else{

                    echo(

            "<script>alert('username  already taken')</script>");

                }

            }

        }

    }

?>

<head>

    <meta charset="UTF-8">

    <meta http-equiv="X-UA-Compatible" content="IE=edge">

    <meta name="viewport" content=

        "width=device-width, initial-scale=1.0">

    <title>Document</title>

    <link rel="stylesheet" type="text/css"

        href="css/style.css" media="screen" />

    <!--  adding bootstrap  -->

    <link rel="stylesheet" href=

        integrity=

"sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm"

        crossorigin="anonymous">

        integrity=

"sha384-KJ3o2DKtIkvYIK3UENzmM7KCkRr/rE9/Qpg6aAZGJwFDMVNA/GpGFF93hXpG5KkN"

        crossorigin="anonymous">

    </script>

    <script src=

        integrity=

"sha384-ApNbgh9B+Y1QKtv3Rn7W3mgPxhU9K/ScQsAP7hUibX39j7fakFPskvXusvfa0b4Q"

        crossorigin="anonymous">

    </script>

    <script src=

        integrity=

"sha384-JZR6Spejh4U02d8jOt6vLEHfe/JQGiRRSQQxSfFWpi1MquVdAyjUar5+76PVCmYl"

        crossorigin="anonymous">

    </script>

    

    <div class="nav-bar">

        <div class="title">

            <h3>welcome to my website</h3>

        </div>

    </div>

</head>

<body>

    <form class="form-register"

        action="register.php" method="POST">

        <div class="form-group">

            <label>username</label>

            <input type="text" class="form-control"

                name="username" id="username"

                aria-describedby="emailHelp"

                placeholder="username" required>

        </div>

        <div class="form-group">

            <label>Email</label>

            <input type="email" class="form-control"

                name="Email" id="Email"

                placeholder="Email" required>

        </div>

        <div class="form-group">

            <label>Password</label>

            <input type="password" class="form-control"

                name="Password" id="Password"

                placeholder="Password" required>

        </div>

        <div class="form-group">

            <label>Password</label>

            <input type="password"

                class="form-control" name="RePassword"

                id="RePassword" placeholder="RePassword"

                required>

        </div>

        <button type="submit"

            class="btn btn-primary btn-lg">

            Register

        </button>

        <button type="button"

            class="btn btn-warning btn-lg"

            id="login-button">

            Already Registered

        </button>

    </form>

    

    <script>

        $("#login-button").click(function () {

            window.location.replace("index.php");

        });

    </script>

</body>

</html>