HTMLでリストを非表示にする方法

var toggleFlag = false;
      function toggleHosptial(e){
          if(!toggleFlag){
              $('.arrow_icon').css({'background-image':'url(' + "../images/arrow_up.png" + ')'})
          }else{
            $('.arrow_icon').css({'background-image':'url(' + "../images/arrow_down.png" + ')'})
          }
        var sibling = e.parentNode.parentNode.children[1];
        $(sibling).toggle();
        toggleFlag = !toggleFlag;
      }