fetch('https://www.dunkindonuts.nl/foodticket/cgi/bestel-nt.cgi?action=get-pickup-info&client_id=5621') .then(response => response.json()) .then(data => { var select = document.querySelector('select'); // eventueel selector aanpassen! select.innerHTML = ''; var appendTo = select; data.forEach(element => { if (element.group_start) { appendTo = document.createElement("optgroup"); appendTo.label = element.group_start; } var option = document.createElement("option"); option.text = element.address+(element.city?', '+element.city:''); option.value = element.id; appendTo.appendChild(option); if (element.group_end) { select.appendChild(appendTo); appendTo = select; } }); });