Google captcha validation with server side

Create Captcha Credential here


HTML:

   

   <form id="registration" name="registration" action="#" method="POST">

        <input type="text" name="name" placeholder="Name" />

        <input type="email" name="email" placeholder="Email" />

        <input type="number" name="number" placeholder="Mobile Number" />

        <input type="password" name="password" placeholder="Password" />

        <div class="form-group">

            <div class="g-recaptcha" data-sitekey="6LcWrMQUAAAAAHbCcCs08zYuhGvdeO16D8WXL-Da" data-callback="verifyRecaptchaCallback" data-expired-callback="expiredRecaptchaCallback"></div>

            <input class="form-control d-none" require data-recaptcha="true" data-error="Please complete the Captcha">

            <div class="help-block with-errors"></div>

        </div>

        <input type="submit" name="submit" value="Register" />

    </form>

JS: 

        var IsCapchaFilled = false;

        // start window onload

        function verifyRecaptchaCallback(e) {

        var formData = new FormData(registration);

        formData.append("g-recaptcha-response", e)

        fetch('php/verify-captcha.php', {

        method: 'post',

        body: formData

        }).then(res => res.json())

        .then(res => {

        if (res.success) {

            IsCapchaFilled = true;

        }

        console.log(res);

        });

        }

        function expiredRecaptchaCallback(e) {

        fetch('php/destroy-captcha.php', {

        method: 'post',

        }).then(res => res.text())

        .then(res => {

        IsCapchaFilled = false;

        });

        }

        var registration = document.querySelector("#registration");

        registration.onsubmit = (e) => {

        e.preventDefault();

        //when form submit just checke IsCapchaFilled

        if (IsCapchaFilled) {

        // do your own code

        }

        else {

        // captcha not verified

        }

        }

PHP:
 inside: php/verify-captcha.php

        <?php 

        session_start();

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

        $captcha_response = $_POST['g-recaptcha-response'];

        $secretKey = "6LcWrMQUAAAAADdsdfsfdsdfUh1MfTGQtPUC7Vc4dbLVF";

        $url = "https://www.google.com/recaptcha/api/siteverify?secret=".$secretKey."&response=".$captcha_response;

        $options = array(

        'http' => array(

        'header'  => "Content-type: application/json",

        'method'  => 'GET',

        )

        );

        $context  = stream_context_create($options);

        $result = file_get_contents($url, false, $context);

        $_SESSION['rCaptcha'] = "true";

        echo $result;

        }

        ?>

Just check when form submit on serverside $_SESSION['rCaptcha']