Unable adding checklist to card using Trello javascript clisent

Question

After the following code snippet is executed, the card is created but the checklist within this card is not. When creating the checklist, the success function is being called with x=0

Expected result: the newly created card should contain checklist with name "Sub Tasks". Why isn't it working?

  var _newCard;
  var name="card name";
  var desc = "card description";
  var boardId = some valisd board id;
  Trello.post("lists/" + idList + "/cards", {
    name: name,
    desc: desc
  }, function(card){
    alert("Card was created");
    _newCard = card;
  });
  Trello.post("checklists", {
      name: "Sub Tasks",
      idBoard: boardId
  }, function(chklist) {
      for (x in _newCard) {
        //alert(x + " is " + _newCard[x]);
      }
      //alert("Checklist id: " + chklist.id);
      Trello.post("cards/" + _newCard.id + "/checklists", {
        value: chklist.id
      }, function(suc) { for (x in suc) { alert(x + " is " + suc[x]); } }, function(err) { alert("Err: " + err) } )
    })