Как отправить id элемента в объект?

const request = new XMLHttpRequest(); 
var steps = document.querySelectorAll('.master-change, .service-change, .date-block'); 
 
// Скрываем все шаги при загрузке страницы 
 
window.onload = function() { 
  steps.forEach((element, index) => { 
    if (index > 0) { 
      element.classList.add('hide'); 
    } 
  }); 
}; 
 
//Переход по шагам 
 
var choiseElement = document.querySelectorAll('.master-list, .service-list'); // Выбираем элементы с которых отлавливаем клик 
 
choiseElement.forEach((element, index) => { 
  element.addEventListener('click', function() { 
    nextStep(element, index); // Вешаем событие на каждый из них 
  }, false); 
}); 
 
var registration = { 
  masterName: '', 
  serviceType: '', 
  time: '' 
}; 
 
function nextStep(el, index) { 
  steps[index].classList.toggle('hide'); // После клика элемент исчезает 
  steps[index + 1].classList.toggle('hide'); // А идущий за ним появляется 
} 
 
const submit = document.querySelector('.btn-submit'); 
 
submit.addEventListener('click', function() { 
  event.preventDefault(); // Отменяем действие по умолчанию 
 
  request.open('GET', './scripts/info.json', true); 
  request.setRequestHeader('Content-type', './scripts/info.json; charset=UTF-8'); 
 
  request.onreadystatechange = function() { 
    if (request.readyState == 4 && request.status == 200) { 
      // alert(request.responseText); 
    } else { 
      console.log(request.status + ' ' + request.statusText); 
    } 
  } 
 
  request.send(); 
 
  console.log(registration); 
});

.hide { 
  display: none; 
}

<main class="pageBody"> 
  <div class="index"> 
    <div class="container"> 
      <div class="form-block"> 
        <form class="form-order" name="form-order"> 
          <div class="from-order__step from-order__step-1 master-change"> 
            <div class="master-list"> 
              <div class="master-list__item" id="master_1"><img class="master-list__photo" src="http://via.placeholder.com/64x64" width="64px" height="64px" alt="Master photo"> 
                <div class="master-name" id="master_1" href="#">Master name</div> 
              </div> 
              <div class="master-list__item" id="master_2"><img class="master-list__photo" src="http://via.placeholder.com/64x64" width="64px" height="64px" alt="Master photo"> 
                <div class="master-name" id="master_2" href="#">Master name</div> 
              </div> 
              <div class="master-list__item" id="master_3"><img class="master-list__photo" src="http://via.placeholder.com/64x64" width="64x" height="64px" alt="Master photo"> 
                <div class="master-name" id="master_3" href="#">Master name</div> 
              </div> 
            </div> 
          </div> 
          <div class="from-order__step from-order__step-2 service-change hide"> 
            <div class="service-list"> 
              <div class="service-list__item" id="service_1"> 
                <h3 class="service__item__name">Service name </h3> 
                <p class="service__item__description">Service description Service description Service description Service description</p><span class="service__price">999 rub</span><span class="service__time">14:44</span> 
              </div> 
              <div class="service-list__item" id="service_2"> 
                <h3 class="service__item__name">Service name </h3> 
                <p class="service__item__description">Service description Service description Service description Service description</p><span class="service__price">999 rub</span><span class="service__time">14:44</span> 
              </div> 
              <div class="service-list__item" id="service_3"> 
                <h3 class="service__item__name">Service name </h3> 
                <p class="service__item__description">Service description Service description Service description Service description</p><span class="service__price">999 rub</span><span class="service__time">14:44</span> 
              </div> 
            </div> 
          </div> 
          <div class="from-order__step from-order__step-3 date-block hide"> 
            <div class="date-block__calendar"> 
              <div class="date-block__time"> 
                <select class="date-block__time"> 
                      <option>10:00</option> 
                      <option>11:00</option> 
                      <option>12:00</option> 
                      <option>13:00</option> 
                      <option>14:00</option> 
                      <option>15:00</option> 
                      <option>16:00</option> 
                      <option>17:00</option> 
                      <option>18:00</option> 
                      <option>19:00</option> 
                      <option>20:00</option> 
                    </select> 
              </div> 
              <button class="btn btn-submit" type="submit">Отправить</button> 
            </div> 
          </div> 
        </form> 
      </div> 
    </div> 
  </div> 
</main>