下拉菜单停止工作

我的页面左侧有一个手风琴菜单。今天我注意到访问量急剧减少，试图找到问题，我发现我的菜单已经停止工作3周前。当我点击箭头时，它会下拉，当我点击有子菜单的菜单时，它仍然打开，在父菜单上高亮显示。现在当我点击产品，我的菜单不再崩溃了。尝试更改类和链接到最新版本的jQuery，但不工作。请帮我弄一下，或者是什么原因使它突然不工作了?

我的网站不工作菜单

<script src="http://code.jquery.com/jquery-3.1.0.min.js" type="text/javascript">
( function( $ ) {
$( document ).ready(function() {
   $('#left li.menu-item-has-children').prepend('<span class="holder"></span>');
   $('#left li.menu-item-has-children > .holder').on('click', this, function(){
      var element = $(this).parent('li');
        if (element.hasClass('open')) {
            element.removeClass('open');
            element.find('li').removeClass('open');
            element.find('ul').slideUp();
        }
        else {
            element.addClass('open');
            element.children('ul').slideDown();
            element.siblings('li').children('ul').slideUp();
            element.siblings('li').removeClass('open');
            element.siblings('li').find('li').removeClass('open');
            element.siblings('li').find('ul').slideUp();
        }
   });
 $('#left li.current-menu-item').addClass('open').children('ul').slideDown();
  });
})(jQuery);
</script>

.uslugi >a{
    color: #F00 !important;
    font-size:16px !important;
    border-bottom: 1px solid rgba(0, 0, 0, 0.04);
}
#left,
#left ul,
#left ul li,
#left ul li a {
  padding: 0;
  list-style: none;
  line-height: 1.5;
  display: block;
  position: relative;
  cursor: pointer;
  text-decoration: none;
  color: #515151;
  margin:0;
  font-family: "Trebuchet MS", Helvetica, sans-serif;
  font-size: 16px;
}
#left ul li a:hover{
color: #000;
background-color: rgba(47, 139, 182, 0.1);
}
.widget.widget_nav_menu li:before{
    display: none;
}
#main-wrapper .widget li:hover{
    background:none;
}
#left ul ul {
  display: none;
  margin: 0 10px;
}
#left ul ul li a {
    cursor: pointer;
padding: 0 5px;
z-index: 1;
color: #344E83;
background: -moz-linear-gradient(right, rgba(255,255,255,1) 0%, rgba(255,255,255,0.91) 98%, rgba(184,238,255,0.81) 100%);
background: -webkit-gradient(right top, left top, color-stop(0%, rgba(255,255,255,1)), color-stop(98%, rgba(255,255,255,0.91)), color-stop(100%, rgba(184,238,255,0.81)));
background: -webkit-linear-gradient(right, rgba(255,255,255,1) 0%, rgba(255,255,255,0.91) 98%, rgba(184,238,255,0.81) 100%);
background: -o-linear-gradient(right, rgba(255,255,255,1) 0%, rgba(255,255,255,0.91) 98%, rgba(184,238,255,0.81) 100%);
background: -ms-linear-gradient(right, rgba(255,255,255,1) 0%, rgba(255,255,255,0.91) 98%, rgba(184,238,255,0.81) 100%);
background: linear-gradient(to left, rgba(255,255,255,1) 0%, rgba(255,255,255,0.91) 98%, rgba(184,238,255,0.81) 100%);
}
#left .menu-item-has-children > a:after {
     content: "";
border-right: 10px solid transparent;
border-left: 10px solid transparent;
margin: 10px 13px 0 0;
border-top: 6px solid #5F5F5F;
position: absolute;
right: 0;
top: 0;
    }
.holder{
border: 1px solid rgba(0, 0, 0, 0.14);
padding: 11px 26px;
z-index: 8;
position: absolute;
margin: 1px -3px 0 0;
right: 0;
background: none;
    }
.holder:hover {
    background: rgba(47, 139, 182, 0.1);
}
#left ul li.open > a,
#left ul li.active > a,
#left ul ul li:hover > a,
#left ul ul li.open > a,
#left ul ul li.active > a,
.current-page-ancestor a {
color: #4686E6;
background-color: rgba(47, 139, 182, 0.2);
}
#left ul ul li:first-child > a {
  box-shadow: none;
}
#left ul ul ul li a {
  padding-left: 30px;
}
@media (min-width:768px) and (max-width:979px){
        .span3{
        width:186px;
        margin-left:0;
    }
}