css - 向下滚动时需要修复引导导航栏以固定

Question

我需要修复以下引导代码，使其在向下滚动时固定在网页顶部。怎么办？请帮助我..

这是我的 Bootstrap 代码。请帮助我在向下滚动网页时将此代码从静态更改为固定。

     <div class="header_top" id="home">
    <nav class="navbar navbar-expand-lg navbar-light bg-light">
        <button class="navbar-toggler navbar-toggler-right mx-auto" type="button" data-toggle="collapse" data-target="#navbarSupportedContent"
            aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
            <span class="navbar-toggler-icon"></span>
        </button>


        <div class="collapse navbar-collapse" id="navbarSupportedContent">
            <ul class="navbar-nav mx-auto">
                <li class="nav-item active">
                    <a class="nav-link" href="index.html">Home
                        <span class="sr-only">(current)</span>
                    </a>
                </li>
                <li class="nav-item">
                    <a class="nav-link" href="about.html">About</a>
                </li>
                <li class="nav-item">
                    <a class="nav-link scroll" href="#menu">Menu</a>
                </li>
                <li class="nav-item">
                    <a class="nav-link" href="blog.html">Blog</a>
                </li>
                <li class="nav-item dropdown">
                    <a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button" data-toggle="dropdown" aria-haspopup="true"
                        aria-expanded="false">
                        Drop Down
                    </a>
                    <div class="dropdown-menu" aria-labelledby="navbarDropdown">
                        <a class="dropdown-item" href="#"></a>
                        <a class="dropdown-item" href="gallery.html">Gallery</a>
                        <div class="dropdown-divider"></div>
                        <a class="dropdown-item" href="404.html">Services</a>

                    </div>
                </li>
                <li class="nav-item">
                    <a class="nav-link" href="contact.html">Contact</a>
                </li>

            </ul>
        </div>
    </nav>

</div>

Answer 1

<nav class="navbar navbar-default navbar-fixed-top">

...

阅读此文档了解更多详情 https://getbootstrap.com/docs/3.3/components/#navbar-fixed-top