如何动态构建包含header的语义ui下拉菜单？

<header>
  <h1>网站标题</h1>
</header>

<div id="menu-container"></div>

header {
  background-color: #f1f1f1;
  padding: 10px;
}

ul.dropdown-menu {
  background-color: #fff;
  border: 1px solid #ccc;
  padding: 10px;
}

ul.dropdown-menu li {
  list-style: none;
  margin-bottom: 5px;
}

ul.dropdown-menu li a {
  text-decoration: none;
  color: #333;
}

var menuData = [
  { label: "菜单项1", link: "链接1" },
  { label: "菜单项2", link: "链接2" },
  { label: "菜单项3", link: "链接3" }
];

var menuContainer = document.getElementById("menu-container");
var dropdownMenu = document.createElement("ul");
dropdownMenu.className = "dropdown-menu";

menuData.forEach(function(item) {
  var menuItem = document.createElement("li");
  var menuLink = document.createElement("a");
  menuLink.href = item.link;
  menuLink.textContent = item.label;
  menuItem.appendChild(menuLink);
  dropdownMenu.appendChild(menuItem);
});

menuContainer.appendChild(dropdownMenu);