javascript - 如果列表 LI 具有使用 jquery 的 UL，则更改 div 的高度对我不起作用

Question

我正在开发一个水平菜单，它对我来说效果很好，但根据设计要求，我需要更改 <div id="nav-subMenu"></div> 的高度如果主/父菜单 li没有任何 ul或者换句话说子菜单。我写的 jquery 对我不起作用我将不胜感激这方面的帮助。

这里是 jsFiddle 的例子

if ($('#nav-wrapper ul li').has('ul'))总是返回 true

示例 jQuery

jQuery(document).ready(function () {

    if ($('#nav-wrapper ul li').hasClass('active')) { //if it does have the class active
        if ($('#nav-wrapper ul li').has('ul')) {
            alert('aaaa');
            $('#nav-subMenu').css("height", "30");
        }
    }
});

示例 HTML 代码

<div id="nav-wrapper">
   <ul class="dropdown dropdown-linear" id="nav">
      <li><span class="dir"><a href="#">Home</a></span></li>
      <li><span class="dir"><a href="#">About Us</a></span></li>
      <li><span class="dir"><a href="Articles.aspx?PageID=5&amp;Language=en-us&amp;ParID=0&amp;Issue=5&amp;CID=1">Articles</a></span></li>
      <li class="active">
         <span class="dir"><a href="Page.aspx?PageID=6&amp;Language=en-us&amp;ParID=0&amp;Issue=5&amp;CID=1">Categories</a></span>
         <ul>
            <li><a href="Page.aspx?PageID=6&amp;Language=1&amp;ParID=6&amp;Issue=1&amp;CID=18">Book Review</a></li>
            <li><a href="Page.aspx?PageID=6&amp;Language=1&amp;ParID=6&amp;Issue=1&amp;CID=16">Business</a></li>
            <li><a href="Page.aspx?PageID=6&amp;Language=1&amp;ParID=6&amp;Issue=1&amp;CID=3">Culture</a></li>
            <li><a href="Page.aspx?PageID=6&amp;Language=1&amp;ParID=6&amp;Issue=1&amp;CID=2">Economy</a></li>
            <li><a href="Page.aspx?PageID=6&amp;Language=1&amp;ParID=6&amp;Issue=1&amp;CID=19">Finance</a></li>
            <li><a href="Page.aspx?PageID=6&amp;Language=1&amp;ParID=6&amp;Issue=1&amp;CID=17">Infrastructure</a></li>
            <li><a href="Page.aspx?PageID=6&amp;Language=1&amp;ParID=6&amp;Issue=1&amp;CID=20">Lifestyle</a></li>
            <li><a href="Page.aspx?PageID=6&amp;Language=1&amp;ParID=6&amp;Issue=1&amp;CID=21">Others</a></li>
            <li><a href="Page.aspx?PageID=6&amp;Language=1&amp;ParID=6&amp;Issue=1&amp;CID=7">People</a></li>
            <li><a href="Page.aspx?PageID=6&amp;Language=1&amp;ParID=6&amp;Issue=1&amp;CID=1">Politics</a></li>
            <li><a href="Page.aspx?PageID=6&amp;Language=1&amp;ParID=6&amp;Issue=1&amp;CID=4">Sports</a></li>
         </ul>
      </li>
      <li><span class="dir"><a href="News.aspx?PageID=3&amp;Language=en-us&amp;ParID=0&amp;Issue=5&amp;CID=1">News</a></span></li>
      <li>
         <span class="dir"><a href="Page.aspx?PageID=12&amp;Language=en-us&amp;ParID=0&amp;Issue=5&amp;CID=1">Archive</a></span>
         <ul>
            <li><a href="Page.aspx?PageID=1&amp;Language=1&amp;ParID=12&amp;Issue=1&amp;CID=1">106</a></li>
            <li><a href="Page.aspx?PageID=3&amp;Language=1&amp;ParID=12&amp;Issue=3&amp;CID=1">102</a></li>
            <li><a href="Page.aspx?PageID=4&amp;Language=1&amp;ParID=12&amp;Issue=4&amp;CID=1">103</a></li>
            <li><a href="Page.aspx?PageID=5&amp;Language=1&amp;ParID=12&amp;Issue=5&amp;CID=1">109</a></li>
         </ul>
      </li>
      <li>
         <span class="dir"><a href="Multimedia.aspx?PageID=10&amp;Language=en-us&amp;ParID=0&amp;Issue=5&amp;CID=1">Multimedia</a></span>
         <ul>
            <li><a href="Videos.aspx?PageID=11&amp;Language=1&amp;ParID=10&amp;Issue=1&amp;CID=1">Video</a></li>
         </ul>
      </li>
   </ul>
</div>
 <div id="nav-subMenu"></div>
<div id="NewsTicker"> </div>

更新:Firebug View 了解何时应触发 jquery 以将高度添加到 DIV

Answer 1

我发现了您的问题，并且它正在按您的要求工作，试试这个:

jQuery(document).ready(function () {
  if ($("#nav-wrapper li.active").length) {
    alert('yes there are .active class');
    if ($(".active").has('ul').length) {
      alert('yes .active class has ul');
      $('#nav-subMenu').css("height", "60px");
    } else {
      alert("NO .active class don't have ul");
      $('#nav-subMenu').css("height", "0px");
    }
  } else {
    alert("NO .active class found.");
  }
});

在此处查看 fiddle :http://jsfiddle.net/zMty8/27/