function _appendFolderList(welTarget, sTargetPath){
            var sURL = _getCorrectedPath(htVar.sMetaInfoURL, sTargetPath);
            var nParentDepth = welTarget.closest(".list-wrap").data("depth") || 0;
            var nNewDepth = nParentDepth + 1;
            _setIndentByDepth(nNewDepth);

            NProgress.start();
            $.ajax(sURL, {
                "success": function(oRes){
                    if(_isListExistsByPath(sTargetPath)){
                        NProgress.done();
                        return;
                    }

                    var aHTML = _getListHTML(oRes.data, sTargetPath);
                    var welTargetItem = $('.listitem[data-path="' + sTargetPath + '"]');
                    var welList = $('<div class="list-wrap" data-listPath="' + sTargetPath + '"></div>');

                    welList.data("depth", nNewDepth);
                    welList.addClass("depth-" + nNewDepth);
                    welList.css("display", "none");
                    welList.html(aHTML);
                    welTargetItem.after(welList);
                    htVar.aWelList.push(welList);

                    if(htVar.aPathQueue.length > 0){
                        _requestFolderList();
                    } else {
                        _setCurrentPathBold(sTargetPath);
                        htVar.aWelList.forEach(function(welList){
                            welList.css("display", "block");
                        });
                    }

                    NProgress.done();
                },
                "error"  : function(){
                    NProgress.done();
                }
            });
        }
@param {Wrapped Element} welTarget
@param {String} sTargetPath