Html 引导导航条卡在移动显示屏上

我的导航栏卡在了它的移动显示屏上，我不知道是什么原因造成的

<div class="collapse navbar-collapse" id="navbarSupportedContent">
    <ul class="navbar-nav mr-auto">
        <li class="nav-item active">
        <a class="nav-link" href="#">Login <span class="sr-only">(current)</span></a>
        </li>
        <li class="nav-item">
            <a class="nav-link" href="#">Register</a>
        </li>
    </ul>
     <!--Search Bar-->
        <form class="form-inline" method = "GET" action = "{% url 'search' %}" >
            <input class="form-control mr-sm-2" name="query"  type="text" placeholder="Zip Code or City/Town">
            <button class="btn btn-outline-success text-white my-2 my-sm-0" type="submit">Search</button>
        </form>
</nav>

导航栏

<div class="collapse navbar-collapse" id="navbarSupportedContent">
    <ul class="navbar-nav mr-auto">
        <li class="nav-item active">
        <a class="nav-link" href="#">Login <span class="sr-only">(current)</span></a>
        </li>
        <li class="nav-item">
            <a class="nav-link" href="#">Register</a>
        </li>
    </ul>
     <!--Search Bar-->
        <form class="form-inline" method = "GET" action = "{% url 'search' %}" >
            <input class="form-control mr-sm-2" name="query"  type="text" placeholder="Zip Code or City/Town">
            <button class="btn btn-outline-success text-white my-2 my-sm-0" type="submit">Search</button>
        </form>
</nav>

搜寻

您使用了错误的引导版本。您使用的是带有alpha版本样式表链接的引导稳定版本代码

<div class="collapse navbar-collapse" id="navbarSupportedContent">
    <ul class="navbar-nav mr-auto">
        <li class="nav-item active">
        <a class="nav-link" href="#">Login <span class="sr-only">(current)</span></a>
        </li>
        <li class="nav-item">
            <a class="nav-link" href="#">Register</a>
        </li>
    </ul>
     <!--Search Bar-->
        <form class="form-inline" method = "GET" action = "{% url 'search' %}" >
            <input class="form-control mr-sm-2" name="query"  type="text" placeholder="Zip Code or City/Town">
            <button class="btn btn-outline-success text-white my-2 my-sm-0" type="submit">Search</button>
        </form>
</nav>

请点击此处查看最新链接：

<div class="collapse navbar-collapse" id="navbarSupportedContent">
    <ul class="navbar-nav mr-auto">
        <li class="nav-item active">
        <a class="nav-link" href="#">Login <span class="sr-only">(current)</span></a>
        </li>
        <li class="nav-item">
            <a class="nav-link" href="#">Register</a>
        </li>
    </ul>
     <!--Search Bar-->
        <form class="form-inline" method = "GET" action = "{% url 'search' %}" >
            <input class="form-control mr-sm-2" name="query"  type="text" placeholder="Zip Code or City/Town">
            <button class="btn btn-outline-success text-white my-2 my-sm-0" type="submit">Search</button>
        </form>
</nav>

更新小提琴

<div class="collapse navbar-collapse" id="navbarSupportedContent">
    <ul class="navbar-nav mr-auto">
        <li class="nav-item active">
        <a class="nav-link" href="#">Login <span class="sr-only">(current)</span></a>
        </li>
        <li class="nav-item">
            <a class="nav-link" href="#">Register</a>
        </li>
    </ul>
     <!--Search Bar-->
        <form class="form-inline" method = "GET" action = "{% url 'search' %}" >
            <input class="form-control mr-sm-2" name="query"  type="text" placeholder="Zip Code or City/Town">
            <button class="btn btn-outline-success text-white my-2 my-sm-0" type="submit">Search</button>
        </form>
</nav>

找工作

您是否遵循引导文档来实现导航栏？除了我更改了链接之外，这完全是从引导网站上获得的