https://www.autohuset-hoersholm.dk/js/recaptha-validation.js

1//'recaptchaSite' variable must be present globally. recommended to set on MasterPages
2
3function addRecaptchaOnPageLoad() {
4    var hiddenField = document.getElementById("RecaptchaToken");
5    if (hiddenField) {
6        loadScript('application/javascript', 'https://www.google.com/recaptcha/api.js?onload=initializeRecaptcha&render=' + recaptchaSite);
7    }
8}
9
10
11function loadScript(type, src) {
12    let scriptElem = document.createElement('script');
13    scriptElem.type = type;
14    scriptElem.src = src;
15    document.head.appendChild(scriptElem);
16}
17
18function initializeRecaptcha() {
19    var hiddenField = document.getElementById("RecaptchaToken");
20    function revalidateCaptcha(delayMs) {
21        setTimeout(function () {
22            grecaptcha.execute(recaptchaSite, { action: 'submit' }).then(function (token) {
23                hiddenField.value = token;
24
25                //Recaptcha token has a two minute time out, and we cannot generate the token before the form submission. Thus we re-generate the token every other minute.
26                revalidateCaptcha((1000 * 60 * 2) - 5);
27            });
28        }, delayMs);
29    }
30
31    revalidateCaptcha(0);
32}
33
34//document ready in plain javascript
35if (document.readyState === "complete" || (document.readyState !== "loading" && !document.documentElement.doScroll)) {
36    //call on next available tick
37    setTimeout(addRecaptchaOnPageLoad, 1);
38} else {
39    document.addEventListener("DOMContentLoaded", function () {
40        addRecaptchaOnPageLoad();
41    });
42}