Я не заставляю его работать.Я думал, что-то простое работает так:
<script>
// This is from Bootstrap 4 Validation Example
(function() {
'use strict';
window.addEventListener('load', function() {
// Fetch all the forms we want to apply custom Bootstrap validation styles to
var forms = document.getElementsByClassName('needs-validation');
// Loop over them and prevent submission
var validation = Array.prototype.filter.call(forms, function(form) {
form.addEventListener('submit', function(event) {
if (form.checkValidity() === false) {
event.preventDefault();
event.stopPropagation();
} else {
grecaptcha.execute();
}
form.classList.add('was-validated');
}, false);
});
}, false);
})();
</script>