<script src="https://www.google.com/recaptcha/api.js?onload=onloadCallbackRecap&render=<?php echo RECAP_CLIENT ?>"></script>
<script>
var onloadCallbackRecap = function () {
grecaptcha.ready(function () {
grecaptcha.execute('<?php echo RECAP_CLIENT ?>', {action: 'contact_callback'}).then(function (token) {
let recapResponse = document.createElement("input");
recapResponse.type = "hidden";
recapResponse.className = "recap_response";
recapResponse.name = "recap_response";
recapResponse.id = "recap_response";
recapResponse.value = token;
//!!! элемент формы
let form = document.querySelector('form[name=SIMPLE_FORM_1]');
form.appendChild(recapResponse);
});
});
};
</script>