javascript - 如何使用JS函数动态更改列表的类

Question

我想根据用户的点击动态更改列表项的类别。我有一个菜单，我想将 .active 类仅分配给用户单击的菜单，并且最初主菜单必须处于事件状态

这是我的代码

function activeclass(id)
{
  document.getElementById(id).className += "active";
}

<section id="menu-area">      
  <nav class="navbar navbar-default" role="navigation">  
    <div class="container">
      <div class="navbar-header">
        <!-- FOR MOBILE VIEW COLLAPSED BUTTON -->
        <button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#navbar" aria-expanded="false" aria-controls="navbar">
          <span class="sr-only">Toggle navigation</span>
          <span class="icon-bar"></span>
          <span class="icon-bar"></span>
          <span class="icon-bar"></span>
          <span class="icon-bar"></span>
        </button>
        <!-- LOGO -->              
        <!-- TEXT BASED LOGO <a class="navbar-brand" href="index.html">Inventive</a>  -->            
        <!-- IMG BASED LOGO  -->
        <a class="navbar-brand" href="index.html"><img class="img-responsive" src="assets/images/logo.png" alt="logo" width="200"></a> 
      </div>
      <div id="navbar" class="navbar-collapse collapse">
        <ul id="top-menu" class="nav navbar-nav navbar-right main-nav">
          @yield('logo')
          <li id="home"><a href="{{ URL::route('index') }}" onclick="activeclass(id)">Home</a></li>
          <li id="aboutus"><a href="{{ URL::route('aboutus') }}" onclick="activeclass(id)">About Us</a></li>
          <li id="products"><a href="{{ URL::route('products') }}" onclick="activeclass(id)">Products</a></li>
          <li id="gallery"><a href="{{ URL::route('gallery') }}" onclick="activeclass(id)" >Gallery</a></li>           
          <li id="contactus"><a href="{{ URL::route('contactus') }}" onclick="activeclass(id)">Contact</a></li>
        </ul>                     
      </div><!--/.nav-collapse -->
    </div>     
  </nav>
</section>

在 CSS 文件中，带有 li 的 active 类将用于突出显示所选页面菜单

Answer 1

尽管有更好的方法来实现您想要的东西(例如 @Jitendra Tiwari 的答案或我下面的示例)，但我想向您指出代码中的问题。

问题在于您向函数 activeclass 传递了一个未知参数:id。

当您调试代码时，您可以看到 id 参数为空:

您需要传递一个带有相关id的字符串参数:

function activeclass(id) {
  document.getElementById(id).className += "active";
}

.active {
  background:red;
}

<nav class="navbar navbar-default" role="navigation">  
  <div class="container">
    <div class="navbar-header">
      <!-- FOR MOBILE VIEW COLLAPSED BUTTON -->
      <button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#navbar" aria-expanded="false" aria-controls="navbar">
        <span class="sr-only">Toggle navigation</span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
      </button>
      <!-- LOGO -->              
      <!-- TEXT BASED LOGO 
<a class="navbar-brand" href="index.html">Inventive</a>  -->            
      <!-- IMG BASED LOGO  -->
      <a class="navbar-brand" href="index.html"><img class="img-responsive" src="assets/images/logo.png" alt="logo" width="200"></a> 
    </div>
    <div id="navbar" class="navbar-collapse collapse">
      <ul id="top-menu" class="nav navbar-nav navbar-right main-nav">
        @yield('logo')
        <li id="home"><a href="#" onclick="activeclass('home')">Home</a></li>
        <li id="aboutus"><a href="#" onclick="activeclass('aboutus')">About Us</a></li>
        <li id="products"><a href="#" onclick="activeclass('products')">Products</a></li>
        <li id="gallery"><a href="#" onclick="activeclass('gallery')" >Gallery</a></li>           
        <li id="contactus"><a href="#" onclick="activeclass('contactus')">Contact</a></li>
      </ul>                     
    </div><!--/.nav-collapse -->
  </div>     
</nav>

http://jsbin.com/dadoqop/edit?html,css,js

此外，请从代码中删除 public 关键字。它不是在 JavaScript 中

一个工作示例没有 jQuery:

[].forEach.call(document.querySelectorAll('#top-menu a'), function(elm) {
  elm.addEventListener('click', function() {
    var active = document.querySelector('.active');
    if (active) {
      active.classList.remove('active');
    }
    elm.parentNode.classList.add('active');  
  });
});

.active {
  background:red;  
}

<nav class="navbar navbar-default" role="navigation">  
  <div class="container">
    <div class="navbar-header">
      <!-- FOR MOBILE VIEW COLLAPSED BUTTON -->
      <button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#navbar" aria-expanded="false" aria-controls="navbar">
        <span class="sr-only">Toggle navigation</span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
      </button>
      <!-- LOGO -->              
      <!-- TEXT BASED LOGO 
<a class="navbar-brand" href="index.html">Inventive</a>  -->            
      <!-- IMG BASED LOGO  -->
      <a class="navbar-brand" href="index.html"><img class="img-responsive" src="assets/images/logo.png" alt="logo" width="200"></a> 
    </div>
    <div id="navbar" class="navbar-collapse collapse">
      <ul id="top-menu" class="nav navbar-nav navbar-right main-nav">
        @yield('logo')
        <li id="home"><a href="#">Home</a></li>
        <li id="aboutus"><a href="#">About Us</a></li>
        <li id="products"><a href="#">Products</a></li>
        <li id="gallery"><a href="#">Gallery</a></li>           
        <li id="contactus"><a href="#">Contact</a></li>
      </ul>                     
    </div><!--/.nav-collapse -->
  </div>     
</nav>