Question

使用引导框架，我试图将导航栏的背景颜色从透明更改为白色。当我使用navbar-shrink类稍微滚动时，它当前正在工作。但是，我只想在导航栏缩小时不立刻进入第一部分标签，就将导航栏的颜色从透明更改为白色...

#mainNav.navbar-shrink {
    border-bottom: 1px solid rgba(33,37,41,.1);
    background-color: #fff;
}

.container {
    background-color: grey;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<link href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css" rel="stylesheet"/>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js"></script>

<nav class="navbar navbar-expand-lg navbar-light fixed-top" id="mainNav">
    <div class="container">
        <button class="navbar-toggler navbar-toggler-right" type="button" data-toggle="collapse" data-target="#navbarResponsive" aria-controls="navbarResponsive" aria-expanded="false" aria-label="Toggle navigation">
            <span class="navbar-toggler-icon"></span>
        </button>
        <div class="collapse navbar-collapse" id="navbarResponsive">
            <ul class="navbar-nav ml-auto">
                <li class="nav-item">
                    <a class="nav-link js-scroll-trigger selected" href="#about">About</a>
                </li>
                <li class="nav-item">
                    <a class="nav-link js-scroll-trigger" href="#services">Services</a>
                </li>
                <li class="nav-item">
                    <a class="nav-link js-scroll-trigger" href="#portfolio">Projects</a>
                </li>
                <li class="nav-item">
                    <a class="nav-link js-scroll-trigger" href="#contact">Contact</a>
                </li>
            </ul>
        </div>
    </div>
</nav>

<section class="bg-primary first" id="about">
    <div class="container">
        <div class="row">
</section>

我希望仅当我滚动到section标签（id = about）时才改变背景颜色，而不是在导航栏缩小时才改变

Answer 1

如果您使用ScrollSpy插件来处理活动导航链接的更新，则可以使用以下解决方案。当#about部分滚动到时，导航栏只会变成白色。

$('[data-spy="scroll"]').on('activate.bs.scrollspy', function (e) {
  var tabId = $(e.target).find('a').attr("href");
  if(tabId == "#about"){
    $("#mainNav").css("background-color","#fff")
  }
})

Answer 2

$(document).ready(function () {
    $(window).on("scroll", function () {
        if ($(window).scrollTop() >= 800) {
            $(".navbar").addClass("navbar-shrink ");
        } else {
            $(".navbar").removeClass("navbar-shrink ");
        }
    });
});

仅在滚动到第一部分标签时

2 个答案: