jquery - Bootstrap 4 - Nav - 隐藏额外的菜单项

Question

我有一个类似这样的 Bootstrap 4 布局: https://www.codeply.com/go/yLO99L66MD

当导航元素太多时，我希望它们被隐藏，所以我添加了这个:nav {overflow:hidden}。这完成了工作，但问题是它也隐藏了我的下拉菜单。如何隐藏额外的菜单项，但仍允许下拉菜单显示可见项？

<nav class="navbar navbar-expand-md navbar-dark bg-dark">
    <a class="navbar-brand" href="#">Navbar</a>
    <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarsExampleDefault" aria-controls="navbarsExampleDefault" aria-expanded="false" aria-label="Toggle navigation">
        <span class="navbar-toggler-icon"></span>
    </button>

    <div class="collapse navbar-collapse" id="navbarsExampleDefault">
        <ul class="navbar-nav mr-auto">
            <li class="nav-item active">
                <a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a>
            </li>
            <li class="nav-item">
                <a class="nav-link" href="#">Link</a>
            </li>
            <li class="nav-item">
                <a class="nav-link disabled" href="#">Disabled</a>
            </li>
            <li class="nav-item dropdown">
                <a class="nav-link dropdown-toggle" href="http://example.com" id="dropdown01" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">Dropdown</a>
                <div class="dropdown-menu" aria-labelledby="dropdown01">
                    <a class="dropdown-item" href="#">Action</a>
                    <a class="dropdown-item" href="#">Another action</a>
                    <a class="dropdown-item" href="#">Something else here</a>
                </div>
            </li>

            <li class="nav-item">
                <a class="nav-link" href="#">aaaaaaaa aaaaa </a>
            </li>

            <li class="nav-item">
                <a class="nav-link" href="#">bbbbbb bbbbb</a>
            </li>

            <li class="nav-item">
                <a class="nav-link" href="#">cccccccc cccccccc </a>
            </li>

            <li class="nav-item">
                <a class="nav-link" href="#">dddd ddddddddd </a>
            </li>
            <li class="nav-item">
                <a class="nav-link" href="#">eeeeeeeeeeeeeeeeee cv kbc vxckjvhkxcv </a>
            </li>


        </ul>

    </div>
</nav>

<div class="container">

    <div class="starter-template">
        <h1>Bootstrap starter template</h1>
        <p class="lead">Use this document as a way to quickly start any new project.
            <br> All you get is this text and a mostly barebones HTML document.</p>
    </div>

</div>
<!-- /.container -->

Answer 1

您可以使用导航栏作为这个给定的示例。

当你调整浏览器大小时，如果没有足够的空间，导航元素将被移动到下拉列表中。

Demo

[1]: http://jsfiddle.net/swasatz/3fn4d5oq/

---

片段演示

以全页模式打开代码段并调整浏览器大小以查看更改。

$(document).ready(function () {
    var menu = $("#nav-bar-filter"),
        subMenu = $(".subfilter"),
        more = $("#more-nav"),
        parent = $(".filter-wrapper"),
        ww = $(window).width(),
        smw = more.outerWidth();

    menu.children("li").each(function () {
        var w = $(this).outerWidth();
        if (w > smw) smw = w + 20;
        return smw
    });
    more.css('width', smw);

    function contract() {
        var w = 0,
            outerWidth = parent.width() - smw - 50;
        for (i = 0; i < menu.children("li").size(); i++) {
            w += menu.children("li").eq(i).outerWidth();
            if (w > outerWidth) {
                menu.children("li").eq(i - 1).nextAll()
                    .detach()
                    .css('opacity', 0)
                    .prependTo(".subfilter")
                    .stop().animate({
                    'opacity': 1
                }, 300);
                break;
            }
        }
    }

    function expand() {
        var w = 0,
            outerWidth = parent.width() - smw - 20;
        menu.children("li").each(function () {
            w += $(this).outerWidth();
            return w;
        });
        for (i = 0; i < subMenu.children("li").size(); i++) {
            w += subMenu.children("li").eq(i).outerWidth();
            if (w > outerWidth) {
                var a = 0;
                while (a < i) {
                    subMenu.children("li").eq(a)
                        .css('opacity', 0)
                        .detach()
                        .appendTo("#nav-bar-filter")
                        .stop().animate({
                        'opacity': 1
                    }, 300);
                    a++;
                }
                break;
            }
        }
    }
    contract();

    $(window).on("resize", function (e) {
        ($(window).width() > ww) ? expand() : contract();
        ww = $(window).width();
    });

});

body {
    font-family: verdana;
    min-width: 250px;
}
ul#more-nav, ul#nav-bar-filter {
    display: inline-block;
    vertical-align: top;
}
ul {
    list-style-type: none;
    padding: 0;
    margin: 0;
}
li {
    padding: 4px 8px 4px 8px;
    margin: 0;
}
#nav-bar-filter li {
    display: inline-block;
    font-weight: bold;
}
a {
    text-decoration: none;
    color: #666;
    font-size: 13px;
}
.filter-wrapper {
    width: 100%;
    background: #eee;
    padding: 5px 10px 5px 10px;
}
#more-nav {
    float: right;
}
.subfilter{
    padding-top: 10px;
}
.subfilter li {
    margin: 0 0 0 20px;
    padding: 5px 0 0 0;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="twelve columns filter-wrapper">
    <ul class="nav-bar-filter" id="nav-bar-filter">
        <li><a href="#">All</a> 
        </li>
        <li><a href="#">Small</a>

        </li>
        <li><a href="#">Medium</a>

        </li>
        <li><a href="#">Extra large</a>

        </li>
        <li><a href="#">Text</a>

        </li>
        <li><a href="#">Small-1</a>

        </li>
        <li><a href="#">Medium-1</a>

        </li>
        <li><a href="#">Extra large text</a>

        </li>
        <li><a href="#">Large text</a>

        </li>
        <li><a href="#">Another text</a>

        </li>
        <li><a href="#">text</a>

        </li>
    </ul>
    <ul id="more-nav">
        <li><b><a href="#">More &gt;</a></b>

            <ul class="subfilter"></ul>
        </li>
    </ul>
</div>