Invisible reCAPTCHA sending empty g-recaptcha-response with multiple forms

Question

I am trying to use Google Invisible reCAPTCHA, but it is sending empty the g-recaptcha-response POST parameter when i have multiple forms in the same page. Here is my code:

Google JS

<script src="//google.com/recaptcha/api.js?hl=pt-BR&onload=captchaCallback&render=explicit" async defer></script>

Form 1

<form action="/site/Contact/send" id="form1">
    <input type="text" name="nome" required>

    <div class="g-recaptcha"
        data-sitekey="xxxxxxxxxxxxxxxxxxxxxxxx"
        data-callback="form1Callback"
        data-size="invisible">
    </div>

    <button type="submit">Send</button>

</form>

Form 2

<form action="/site/Contact/send" id="form2">
    <input type="text" name="nome" required>

    <div class="g-recaptcha"
        data-sitekey="xxxxxxxxxxxxxxxxxxxxxxxx"
        data-callback="form2Callback"
        data-size="invisible">
    </div>

    <button type="submit">Send</button>
</form>

My JS (Based on this answer]

$(document).ready(function() {

    window.captchaCallback = function(){
        $('.g-recaptcha').each(function(index, el) {
            var attributes = {
                'sitekey'  : $(el).data('sitekey'),
                'size'     : $(el).data('size'),
                'callback' : $(el).data('callback')
            };

            grecaptcha.render(el, attributes);
        });
    };

    window.form1Callback = function(){
         $('#form1').submit();
    };

    window.form2Callback = function(){
         $('#form2').submit();
    };
});

When i submit one of these forms the g-recaptcha-response parameter is sent empty, as below.

Can someone help me to put it to work, please?

Answer 1

You will need to manually call grecaptcha.execute() to run recaptcha if you are rendering invisible recaptcha in a div element. Also if there are multiple forms with recaptcha, then the grecaptcha.execute() method needs to be called with a widget ID generated for each recaptcha when the grecaptcha.render() method is called.

$(document).ready(function() {
    window.captchaCallback = function(){
        $('.g-recaptcha').each(function(index, el) {
            var attributes = {
                'sitekey'  : $(el).data('sitekey'),
                'size'     : $(el).data('size'),
                'callback' : $(el).data('callback')
            };

            $(el).data('recaptcha-widget-id', grecaptcha.render(el, attributes));
        });
    };

    window.form1Callback = function(){
        $('#form1').data("recaptcha-verified", true).submit();
    };

    window.form2Callback = function(){
        $('#form2').data("recaptcha-verified", true).submit();
    };

    $('#form1,#form2').on("submit", function(e){
        var $form = $(this);
        if ($form.data("recaptcha-verified")) return;

        e.preventDefault();
        grecaptcha.execute($form.find(".g-recaptcha").data("recaptcha-widget-id"));
    });
});