How can I call a function after grecaptcha.execute() has finished executing - triggered by an event?

问题

Currently grecaptcha.execute is being executed on page load as in the first JS example below. If reCAPTCHA challenge is triggered this happens when the page has loaded. Ideally this would happen when the form submit button is clicked instead. So I've tried this by moving this into the submit event (second JS example) and put the axios function into a promise. It's submitting before grecaptcha.execute has finished executing.

What is it that I'm not understanding here? My first experience with promises so am I not understanding how promises work? Is that not the best solution for this problem? Is is something else entirely?

HTML

<head>
<script src="https://www.google.com/recaptcha/api.js?onload=onloadCallback&render=explicit" defer></script>
</head>

const form = document.querySelector('#subscribe');
let recaptchaToken;
const recaptchaExecute = (token) => {
    recaptchaToken = token;
};


const onloadCallback = () => {
    grecaptcha.render('recaptcha', {
        'sitekey': 'abcexamplesitekey',
        'callback': recaptchaExecute,
        'size': 'invisible',
    });
    grecaptcha.execute();
};

    form.addEventListener('submit', (e) => {
        e.preventDefault();
        const formResponse = document.querySelector('.js-form__error-message');
        axios({
            method: 'POST',
            url: '/actions/newsletter/verifyRecaptcha',
            data: qs.stringify({
                recaptcha: recaptchaToken,
                [window.csrfTokenName]: window.csrfTokenValue,

            }),
            config: {
                headers: {
                    'Content-Type': 'application/x-www-form-urlencoded',
                },
            },
        }).then((data) => {
            if (data && data.data.success) {
                formResponse.innerHTML = '';
                form.submit();
            } else {
                formResponse.innerHTML = 'Form submission failed, please try again';
            }
        });
    }

const onloadCallback = () => {
    grecaptcha.render('recaptcha', {
        'sitekey': 'abcexamplesitekey',
        'callback': recaptchaExecute,
        'size': 'invisible',
    });
};

form.addEventListener('submit', (e) => {
    e.preventDefault();
    const formResponse = document.querySelector('.js-form__error-message');
    grecaptcha.execute().then(axios({
        method: 'POST',
        url: '/actions/newsletter/verifyRecaptcha',
        data: qs.stringify({
            recaptcha: recaptchaToken,
            [window.csrfTokenName]: window.csrfTokenValue,
        }),
        config: {
            headers: {
                'Content-Type': 'application/x-www-form-urlencoded',
            },
        },
    })).then((data) => {
        if (data && data.data.success) {
            formResponse.innerHTML = '';
            form.submit();
        } else {
            formResponse.innerHTML = 'Form submission failed, please try again';
        }
    });
}

回答1:

The way I resolved this is by changing the submit button into a dumb button, and handling everything in a js method:

@Html.HiddenFor(model => model.ReCaptchaToken);

<input type="button"
        value="Submit"
        onclick="onSubmit()"
/>

Then() method waits for the token, puts it in a hidden field, and only then manually submits the form:

<script>
    if (typeof grecaptcha == 'object') { //undefined behind the great firewall
        grecaptcha.execute('@Config.ReCaptchaSiteKey', { action: 'register' }).then(function (token) {
            window.document.getElementById('ReCaptchaToken').value = token;
            $('form').submit();
        });
    } else {
        window.document.getElementById('ReCaptchaToken').value = -1;
        $('form').submit();
    }
</script>

Note: @Html.HiddenFor is MVC - you might not use that. $('form') is JQuery - you don't necessarily need that - can use getElementById as well.

回答2:

I'm using a web service, as I wanted a method that I could use in all pages. Special attention to the fact you need to return false; and when the ajax request returns, do your post back.

<script type="text/javascript">

   function CheckCaptcha()
    {
        grecaptcha.ready(function () {
            grecaptcha.execute('<%#RecaptchaSiteKey%>', { action: 'homepage' }).then(function (token) {
            $.ajax({
                type: "POST",
                url: "../WebServices/Captcha.asmx/CaptchaVerify", 
                data: JSON.stringify({ 'captchaToken' : token }),
                contentType: "application/json; charset=utf-8",
                dataType: "json",
                success: function (response) {
                    __doPostBack('<%= RegisterButton.UniqueID%>', '');
                    //console.log('Passed the token successfully');
                },
                failure: function (response) {                     
                    //alert(response.d);
                }
                });
            });
       });

       return false;
    }
    </script>

来源：https://stackoverflow.com/questions/54876600/how-can-i-call-a-function-after-grecaptcha-execute-has-finished-executing-tr

标签

javascript

ajax

promise

axios

grecaptcha