tsv08kulmbach-website/public/assets/js/form.js

/* Formulare: Progressive Enhancement — ohne JS normales POST + Redirect.
   Mit JS: Inline-Feldfehler (aria-describedby, Fokus aufs erste ungültige Feld),
   fetch-Submit, Status in aria-live-Region, Button-Sperre während des Sendens. */
(function () {
    'use strict';

    var form = document.querySelector('.form');
    if (!form || !window.fetch) {
        return;
    }

    var status = form.querySelector('[data-form-status]');
    var button = form.querySelector('button[type="submit"]');

    var MESSAGES = {
        success: 'Danke für deine Anfrage! Wir melden uns so schnell wie möglich bei dir.',
        validation: 'Bitte prüfe deine Eingaben – Pflichtfelder fehlen oder die E-Mail-Adresse ist ungültig.',
        mail: 'Deine Nachricht konnte gerade nicht versendet werden. Bitte versuche es später erneut.'
    };

    function errorEl(field) {
        return field.id ? document.getElementById(field.id + '-error') : null;
    }

    function showFieldError(field) {
        var msg = errorEl(field);
        field.setAttribute('aria-invalid', 'true');
        if (msg) {
            msg.textContent = field.validationMessage;
            msg.hidden = false;
        }
    }

    function clearFieldError(field) {
        var msg = errorEl(field);
        field.removeAttribute('aria-invalid');
        if (msg) {
            msg.textContent = '';
            msg.hidden = true;
        }
    }

    Array.prototype.forEach.call(form.elements, function (field) {
        field.addEventListener('input', function () { clearFieldError(field); });
        field.addEventListener('change', function () { clearFieldError(field); });
    });

    function show(type, text) {
        var p = document.createElement('p');
        p.className = type === 'success' ? 'form__success' : 'form__error';
        p.textContent = text;
        status.replaceChildren(p);
        status.focus({ preventScroll: true });
        status.scrollIntoView({ block: 'nearest', behavior: 'smooth' });
    }

    form.addEventListener('submit', function (event) {
        if (!form.checkValidity()) {
            event.preventDefault();
            var invalid = form.querySelectorAll(':invalid');
            Array.prototype.forEach.call(invalid, showFieldError);
            if (invalid.length) {
                invalid[0].focus();
            }
            return;
        }

        event.preventDefault();
        button.disabled = true;
        button.textContent = 'Wird gesendet …';

        fetch(form.action, {
            method: 'POST',
            body: new FormData(form),
            headers: { Accept: 'application/json' }
        })
            .then(function (response) { return response.json(); })
            .then(function (data) {
                if (data.ok) {
                    show('success', MESSAGES.success);
                    form.reset();
                } else {
                    show('error', MESSAGES[data.error] || MESSAGES.mail);
                }
            })
            .catch(function () {
                show('error', MESSAGES.mail);
            })
            .finally(function () {
                button.disabled = false;
                button.textContent = 'Nachricht senden';
            });
    });
})();