Как правильно указать top координаты

function showTooltipCard(id_profile, position, target) { 
  var tooltip_card = ge("tooltip_card"); 
  var client_x = document.documentElement.clientWidth; 
  var client_y = document.documentElement.clientHeight; 
  var left, top; 
 
  var card_header = ge("card_header"); 
  var card_icon = ge("card_icon"); 
  var card_user_name = ge("card_user_name"); 
  var url = "/?act=card"; 
  ajax.post({ 
    url: url, 
    data: "user_id=" + id_profile, 
    callback: function(data) { 
      var response = JSON.parse(data); 
      if (response.error) { 
        Box.info("Ошибка", response.error.msg); 
        return; 
      } 
      card_header.style.backgroundImage = "url(" + response.card.backgroundHeader + ")"; 
      card_icon.style.backgroundImage = "url(" + response.card.backgroundIcon + ")"; 
      card_user_name.innerHTML = response.card.userName; 
      card_user_name.href = "/id" + id_profile; 
 
      tooltip_card.classList.remove("none"); 
 
      /** 
      * здесь top координаты 
      */ 
  
      left = position['left'] + (target.offsetWidth - tooltip_card.offsetWidth) / 2; 
 
      tooltip_card.style.left = left + "px"; 
      tooltip_card.style.top = top + "px"; 
 
      console.log("position Y " + position['y']); 
      console.log("client Y " + client_y); 
      console.log("offsetHeight " + tooltip_card.offsetHeight); 
      console.log("---------------------------------------------"); 
    } 
  }); 
}