动态添加的对象赢得't在javascript中拾取样式

我动态添加的对象不会完全拾取样式。我有这些html对象：

<div id="cssmenu">
    <ul id="buttonsDiv">
    </ul>
</div>

我添加了几个li元素：

for (var i = 0; i < numOfDays; i++) {
    let j=i;        
    var newButton = $("<li class='active has-sub'><a href='#'><span> Day " + (i + 1) +  "</span></a><ul id=button" + (i + 1) + "></ul></li>");
    $("#buttonsDiv").append(newButton);
}

点击某个对象后，我想插入子菜单项：

function addEvents(attraction)
{
   var newButton = $("<li><a href='#'><span>"+ attraction+ "</span></a></li>");
   var ulChildren = document.getElementById('buttonsDiv').children;
   var childrenLength = ulChildren.length;
   for(var i = 0; i < childrenLength; i++){
     if(ulChildren[i].children[1].id == day){
       $(ulChildren[i].children[1]).append(newButton);
     }
   }
}

现在，当我"检查"web上的元素（它们正在被添加）时，插入操作正在按预期进行。但由于某些原因，它没有得到正确的样式，当我对对象进行硬编码时，我会得到所需的效果。这与DOM不识别我的新元素有关吗？

有人能给我指正确的方向吗？

编辑：这是我的CSS文件的链接：

http://triprecommendation.azurewebsites.net/project/buttons_styles.css

CSS:

#cssmenu,
#cssmenu ul,
#cssmenu ul li,
#cssmenu ul li a {
  margin: 0;
  padding: 0;
  border: 0;
  list-style: none;
  line-height: 1;
  display: block;
  position: relative;
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
}
#cssmenu {
  width: 200px;
  font-family: Helvetica, Arial, sans-serif;
  color: #ffffff;
}
#cssmenu ul ul {
  display: none;
}
.align-right {
  float: right;
}
#cssmenu > ul > li > a {
  padding: 15px 20px;
  border-left: 1px solid #1682ba;
  border-right: 1px solid #1682ba;
  border-top: 1px solid #1682ba;
  cursor: pointer;
  z-index: 2;
  font-size: 14px;
  font-weight: bold;
  text-decoration: none;
  color: #ffffff;
  text-shadow: 0 1px 1px rgba(0, 0, 0, 0.35);
  background: #36aae7;
  background: -webkit-linear-gradient(#36aae7, #1fa0e4);
  background: -moz-linear-gradient(#36aae7, #1fa0e4);
  background: -o-linear-gradient(#36aae7, #1fa0e4);
  background: -ms-linear-gradient(#36aae7, #1fa0e4);
  background: linear-gradient(#36aae7, #1fa0e4);
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.15);
}
#cssmenu > ul > li > a:hover,
#cssmenu > ul > li.active > a,
#cssmenu > ul > li.open > a {
  color: #eeeeee;
  background: #1fa0e4;
  background: -webkit-linear-gradient(#1fa0e4, #1992d1);
  background: -moz-linear-gradient(#1fa0e4, #1992d1);
  background: -o-linear-gradient(#1fa0e4, #1992d1);
  background: -ms-linear-gradient(#1fa0e4, #1992d1);
  background: linear-gradient(#1fa0e4, #1992d1);
}
#cssmenu > ul > li.open > a {
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.15), 0 1px 1px rgba(0, 0, 0, 0.15);
  border-bottom: 1px solid #1682ba;
}
#cssmenu > ul > li:last-child > a,
#cssmenu > ul > li.last > a {
  border-bottom: 1px solid #1682ba;
}
.holder {
  width: 0;
  height: 0;
  position: absolute;
  top: 0;
  right: 0;
}
.holder::after,
.holder::before {
  display: block;
  position: absolute;
  content: "";
  width: 6px;
  height: 6px;
  right: 20px;
  z-index: 10;
  -webkit-transform: rotate(-135deg);
  -moz-transform: rotate(-135deg);
  -ms-transform: rotate(-135deg);
  -o-transform: rotate(-135deg);
  transform: rotate(-135deg);
}
.holder::after {
  top: 17px;
  border-top: 2px solid #ffffff;
  border-left: 2px solid #ffffff;
}
#cssmenu > ul > li > a:hover > span::after,
#cssmenu > ul > li.active > a > span::after,
#cssmenu > ul > li.open > a > span::after {
  border-color: #eeeeee;
}
.holder::before {
  top: 18px;
  border-top: 2px solid;
  border-left: 2px solid;
  border-top-color: inherit;
  border-left-color: inherit;
}
#cssmenu ul ul li a {
  cursor: pointer;
  border-bottom: 1px solid #32373e;
  border-left: 1px solid #32373e;
  border-right: 1px solid #32373e;
  padding: 10px 20px;
  z-index: 1;
  text-decoration: none;
  font-size: 13px;
  color: #eeeeee;
  background: #49505a;
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.1);
}
#cssmenu ul ul li:hover > a,
#cssmenu ul ul li.open > a,
#cssmenu ul ul li.active > a {
  background: #424852;
  color: #ffffff;
}
#cssmenu ul ul li:first-child > a {
  box-shadow: none;
}
#cssmenu ul ul ul li:first-child > a {
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.1);
}
#cssmenu ul ul ul li a {
  padding-left: 30px;
}
#cssmenu > ul > li > ul > li:last-child > a,
#cssmenu > ul > li > ul > li.last > a {
  border-bottom: 0;
}
#cssmenu > ul > li > ul > li.open:last-child > a,
#cssmenu > ul > li > ul > li.last.open > a {
  border-bottom: 1px solid #32373e;
}
#cssmenu > ul > li > ul > li.open:last-child > ul > li:last-child > a {
  border-bottom: 0;
}
#cssmenu ul ul li.has-sub > a::after {
  display: block;
  position: absolute;
  content: "";
  width: 5px;
  height: 5px;
  right: 20px;
  z-index: 10;
  top: 11.5px;
  border-top: 2px solid #eeeeee;
  border-left: 2px solid #eeeeee;
  -webkit-transform: rotate(-135deg);
  -moz-transform: rotate(-135deg);
  -ms-transform: rotate(-135deg);
  -o-transform: rotate(-135deg);
  transform: rotate(-135deg);
}
#cssmenu ul ul li.active > a::after,
#cssmenu ul ul li.open > a::after,
#cssmenu ul ul li > a:hover::after {
  border-color: #ffffff;
}

手动工作示例：

    <div id='cssmenu'>
<ul> <!-- buttonsDiv-->
   <li><a href='#'><span>Home</span></a></li>
   <li class='active has-sub'><a href='#'><span>Products</span></a>
       <ul>
         <li><a href='#'><span>Product 1</span></a></li>
         <li><a href='#'><span>Product 2</span></a></li>
         <li><a href='#'><span>Pro 2</span></a></li>
      </ul>
   </li>
   <li><a href='#'><span>About</span></a></li>
   <li class='active has-sub'><a href='#'><span>Contact</span></a>
      <ul>
         <li><a href='#'><span>Product 1</span></a></li>
      </ul>
   </li>
</ul>
</div>