Css 如何实现引导Navbar下拉菜单

如何实现引导4导航栏下拉菜单。我正在使用class.navvbar bottom使其水平**

.navbar底部类，用于将滚动条添加到navbar**

.navbar-bottom {
    overflow-x: auto;
    white-space: nowrap;
}

HTML

这就是如何将下拉菜单添加到导航栏菜单项的方法。不要忘记在HTML文件中添加CSS和JS的引导CDN。此外，不需要navbar底部类来使navbar水平

<nav class="navbar navbar-expand navbar-light navbar-bottom">
    <ul class="navbar-nav mr-auto pl-2">
        <li class="nav-item"><a class="nav-link px-6" href="#">Menu Item</a></li>
        <li class="nav-item">
            <div class="dropdown">
                <a class="nav-link" href="#" class="dropdown-toggle" data-toggle="dropdown">Dropdown</a>
                <div class="dropdown-menu">
                    <a href="#" class="dropdown-item">Dropdown1</a>
                    <a href="#" class="dropdown-item">Dropdown2</a>
                    <a href="#" class="dropdown-item">Dropdown3</a>
                    <a href="#" class="dropdown-item">Dropdown4</a>
                </div>
            </div>
        </li>
        <li class="nav-item"><a class="nav-link px-6" href="#">Menu Item</a></li>
        .........................................................................
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        <li class="nav-item"><a class="nav-link px-6" href="#">Menu Item</a></li>
    </ul>
</nav>

<nav class="navbar navbar-expand navbar-light">
    <ul class="navbar-nav mr-auto pl-2">
        <li class="nav-item"><a class="nav-link px-6" href="#">Menu Item</a></li>
        <li class="nav-item">
            <div class="dropdown">
                <a class="nav-link" href="#" class="dropdown-toggle" data-toggle="dropdown">Dropdown</a>
                <div class="dropdown-menu">
                    <a href="#" class="dropdown-item">Dropdown1</a>
                    <a href="#" class="dropdown-item">Dropdown2</a>
                    <a href="#" class="dropdown-item">Dropdown3</a>
                    <a href="#" class="dropdown-item">Dropdown4</a>
                </div>
            </div>
        </li>
        <li class="nav-item"><a class="nav-link px-6" href="#">Menu Item</a></li>
        .........................................................................
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        <li class="nav-item"><a class="nav-link px-6" href="#">Menu Item</a></li>
    </ul>
</nav>