function updateCart() {
  var form = document.getElementById('ordersubmit');
  var field = document.createElement('input');
  field.type = 'hidden';
  field.name = 'CartV2.GotoStep1';
  field.id = 'CartV2.GotoStep1';
  field.value = 'Update';
  form.appendChild(field);
  form.submit();
}