Question

我想在点击时更改下拉列表中导航项目的背景。并且在屏幕分辨率低于992px时，单击切换按钮后会出现导航菜单，但这不是问题，问题是下拉菜单中的子菜单很难理解谁显示的子菜单。我想解决这个问题。

以下是我的HTML代码。

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Index</title>
    <!-- bootstrap link -->
    <link rel="stylesheet" type="text/css" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css">
    <!-- Custom css -->
    <link rel="stylesheet" href="css/custom.css">
    <!-- JQuery3.2.1 -->
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>    
    <!-- Bootstrap  -->
    <script type="text/javascript" src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.11.0/umd/popper.min.js" integrity="sha384-b/U6ypiBEHpOf/4+1nzFpr53nxSS+GLCkfwBdFNTxtclqqenISfwAzpKaMNFNmj4" crossorigin="anonymous"></script>
</head>
<body>
<nav class="navbar navbar-expand-lg">
  <a class="navbar-brand" href="#">Navbar</a>
  <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#mainNav" aria-controls="mainNav" aria-expanded="false" aria-label="Toggle navigation">
    <span class="navbar-toggler-icon"></span>
  </button>
  <div class="collapse navbar-collapse" id="mainNav">
        <ul class="navbar-nav">
              <li class="nav-item active">
                <a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a>
              </li>
              <!-- Trekking In Nepal -->
              <li class="nav-item dropdown">
                    <a class="nav-link dropdown-toggle" href="" id="navbarDropdownMenuLink" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
                      Trekking in Nepal
                    </a>
                    <ul class="dropdown-menu" aria-labelledby="navbarDropdownMenuLink">
                      <li class="dropdown-submenu">
                        <a class="dropdown-item dropdown-toggle" href="#">Annapurna Region</a>
                            <ul class="dropdown-menu">
                                  <li>
                                    <a class="dropdown-item submenuNav " href="#">Annapurna Circuit</a>
                                  </li>
                                  <li>
                                    <a class="dropdown-item submenuNav " href="#"> Annapurna Base Camp</a>
                                  </li>
                                  <li>
                                    <a class="dropdown-item submenuNav " href="#"> Upper Mustang</a>
                                  </li>
                            </ul>
                      </li>

                      <li class="dropdown-submenu">
                        <a class="dropdown-item dropdown-toggle" href="#">Everest Region</a>
                            <ul class="dropdown-menu">
                                  <li>
                                    <a class="dropdown-item submenuNav " href="#">Everest Base Camp</a>
                                  </li>
                                  <li>
                                    <a class="dropdown-item submenuNav " href="#"> Jiri to Everest Base Camp</a>
                                  </li>
                                  <li>
                                    <a class="dropdown-item submenuNav " href="#"> Everest Three Pass</a>
                                  </li>
                            </ul>
                      </li>

                      <li class="dropdown-submenu">
                        <a class="dropdown-item dropdown-toggle" href="#">Langtang Region</a>
                            <ul class="dropdown-menu">
                                  <li>
                                    <a class="dropdown-item submenuNav " href="#">Langtang Helambu</a>
                                  </li>
                                  <li>
                                    <a class="dropdown-item submenuNav " href="#"> Langtang Gosaikunda Lake</a>
                                  </li>
                                  <li>
                                    <a class="dropdown-item submenuNav " href="#">Langtang Valley</a>
                                  </li>
                            </ul>
                      </li>

                    </ul>
              </li>
        </ul>
  </div>
</nav>
<!-- Custom js -->
<script src="js/custom.js"></script>

</body>
</html>

以下是我在custom.css中写的内容

.navbar-collapse .navbar-nav .dropdown .dropdown-menu{
    margin-left: 0px !important;
    margin-top: 0px !important;
}
.dropdown-submenu {
  position: relative;
}
.dropdown-submenu a::after {
  transform: rotate(-90deg);
  position: absolute;
  right: 6px;
  top: .8em;
  transition: all 0.3s ease-in-out 0s;
}

.dropdown-submenu .dropdown-menu {
  top: 0;
  left: 100%;
  margin-left: .1rem;
  margin-right: .1rem;
}
.dropdown:hover>.dropdown-menu{
    display: block;
}
.dropdown-submenu:hover>.dropdown-menu{
    display: block;
}
@media only screen and (max-width: 991px) {
   .dropdown-submenu a::after {
  transform: rotate(-90deg);
  position: absolute;
  right: 6px;
  top: .8em;
  transition: all 0.3s ease-in-out 0s;
}
}
.submenuNav{
    opacity: 0.8;
    margin-right: 3px;
}
.submenuNav:hover{
    opacity: 1;
    transform: translateX(3px);
    transition: 0.4s all ease;
    margin-right: 0px;
}
.dropdown-item{
    background-color: none !important;
    color: #007bff;
    opacity: 0.8;
}
.dropdown-item:hover{
    background-color: none !important;
    color: #007bff;
    opacity: 1;
    transition: 0.2s all ease;
}
.customNav{
    background-color: none !important;
    color:#007bff !important;
}
.navbar .navbar-toggler .navbar-toggler-icon{
 background-color: #007bff;
 }

以下是我在custom.js中编写的js文件

$(document).ready(function(){
  $(".dropdown-item").click(function(){
    $(this).addClass("customNav");
  });
});

Answer 1

你在说：

我想在点击下拉列表时更改导航项目的背景

在这种情况下，您需要为bitcode标签更改/设置active css选择器，如下所示：

更多信息：

https://www.w3schools.com/cssref/sel_active.asp

我在悬停时有修复导航下拉菜单，如下所述

1 个答案: