How can I make a favorites counter?

Question

JavaScript

Good evening! help to make a counter when you click on the add to favorites button (so that when you click on your favorites, (1) (2) appears, etc. I hope for your help.

<div class="item-img">
                  <div class="item-img-line">
                    {% if _user %}
                      {% if row._faved %}<a href="#" class="fav faved" onclick="return fav({{row.id}});"><i class="icon-star"></i></a>
                      {% else %}<a href="#" class="fav" onclick="return fav({{row.id}});"><i class="icon-star-empty"></i></a>
                      {% endif %}
                    {% else %}
                      <a href="/signin/" class="fav"><i class="icon-star-empty"></i></a>
                    {% endif %}<span>№ {{row.id}}</span>
                  </div>

function fav(id)
{
  if ($(".item[data-id="+id+"]").length) // in thumbnail 
  {
    var el = $(".item[data-id="+id+"] .fav");

    el.toggleClass('faved');

    if (el.hasClass('faved')) el.html('<i class="icon-star"></i>');
    else el.html('<i class="icon-star-empty"></i>');	
  }

  if ($("#item[data-id="+id+"]").length) // in page
  {
    var el = $("#item[data-id="+id+"] .fav");

    el.toggleClass('faved');

    if (el.hasClass('faved')) el.html('Убрать из избранного<i class="icon-star"></i>');
    else el.html('Добавить в избранное<i class="icon-star-empty"></i>');	
  }

  $.ajax({url: "/auth", method: 'post', data: {'fav': id}, async: 'true', cache: 'false'});

  return false;
}