滚动监听(Scrollspy)

滚动监听插件会根据滚动的位置，自动更新导航条的目标，以指示当前窗口中处于活动的状态（滚动在导航条下面的区域，查看active类的改变。弹出菜单的子项也同样会被高亮）。

运行原理

Scrollspy滑动监控组件正常运行的几个要点:

如果从源代码构建JS，请包括 util.js。
它必须在Bootstrap nav 导航组年或 list group列表组上使用。
Scrollspy 需要在你监控的元素上使用 position: relative; ，通常是 <body>。
当需要对 <body>以外的元素进行监控时，请确保具有 height 高度值和 overflow-y: scroll; 属性。
锚点 (<a>)是必须的，并且必须指向一个id上。

实施成功后，你的导航或列表群组将相应地更新，根据 .active 关联的目标，从一个项目移到另一个项目。

滚动导航栏下方的区域，并观看活动列表的变化，下拉项目也会突出显示，如下例所示：

@fat

Ad leggings keytar, brunch id art party dolor labore. Pitchfork yr enim lo-fi before they sold out qui. Tumblr farm-to-table bicycle rights whatever. Anim keffiyeh carles cardigan. Velit seitan mcsweeney's photo booth 3 wolf moon irure. Cosby sweater lomo jean shorts, williamsburg hoodie minim qui you probably haven't heard of them et cardigan trust fund culpa biodiesel wes anderson aesthetic. Nihil tattooed accusamus, cred irony biodiesel keffiyeh artisan ullamco consequat.

@mdo

Veniam marfa mustache skateboard, adipisicing fugiat velit pitchfork beard. Freegan beard aliqua cupidatat mcsweeney's vero. Cupidatat four loko nisi, ea helvetica nulla carles. Tattooed cosby sweater food truck, mcsweeney's quis non freegan vinyl. Lo-fi wes anderson +1 sartorial. Carles non aesthetic exercitation quis gentrify. Brooklyn adipisicing craft beer vice keytar deserunt.

one

Occaecat commodo aliqua delectus. Fap craft beer deserunt skateboard ea. Lomo bicycle rights adipisicing banh mi, velit ea sunt next level locavore single-origin coffee in magna veniam. High life id vinyl, echo park consequat quis aliquip banh mi pitchfork. Vero VHS est adipisicing. Consectetur nisi DIY minim messenger bag. Cred ex in, sustainable delectus consectetur fanny pack iphone.

two

In incididunt echo park, officia deserunt mcsweeney's proident master cleanse thundercats sapiente veniam. Excepteur VHS elit, proident shoreditch +1 biodiesel laborum craft beer. Single-origin coffee wayfarers irure four loko, cupidatat terry richardson master cleanse. Assumenda you probably haven't heard of them art party fanny pack, tattooed nulla cardigan tempor ad. Proident wolf nesciunt sartorial keffiyeh eu banh mi sustainable. Elit wolf voluptate, lo-fi ea portland before they sold out four loko. Locavore enim nostrud mlkshk brooklyn nesciunt.

three

Keytar twee blog, culpa messenger bag marfa whatever delectus food truck. Sapiente synth id assumenda. Locavore sed helvetica cliche irony, thundercats you probably haven't heard of them consequat hoodie gluten-free lo-fi fap aliquip. Labore elit placeat before they sold out, terry richardson proident brunch nesciunt quis cosby sweater pariatur keffiyeh ut helvetica artisan. Cardigan craft beer seitan readymade velit. VHS chambray laboris tempor veniam. Anim mollit minim commodo ullamco thundercats.

<nav id="navbar-example2" class="navbar navbar-light bg-light">
  <a class="navbar-brand" href="#">Navbar</a>
  <ul class="nav nav-pills">
    <li class="nav-item">
      <a class="nav-link" href="#fat">@fat</a>
    </li>
    <li class="nav-item">
      <a class="nav-link" href="#mdo">@mdo</a>
    </li>
    <li class="nav-item dropdown">
      <a class="nav-link dropdown-toggle" data-toggle="dropdown" href="#" role="button" aria-haspopup="true" aria-expanded="false">Dropdown</a>
      <div class="dropdown-menu">
        <a class="dropdown-item" href="#one">one</a>
        <a class="dropdown-item" href="#two">two</a>
        <div role="separator" class="dropdown-divider"></div>
        <a class="dropdown-item" href="#three">three</a>
      </div>
    </li>
  </ul>
</nav>
<div data-spy="scroll" data-target="#navbar-example2" data-offset="0">
  <h4 id="fat">@fat</h4>
  <p>...</p>
  <h4 id="mdo">@mdo</h4>
  <p>...</p>
  <h4 id="one">one</h4>
  <p>...</p>
  <h4 id="two">two</h4>
  <p>...</p>
  <h4 id="three">three</h4>
  <p>...</p>
</div>

嵌套的导航示例

Scrollspy滚动监控也适用于嵌套的 .nav。如果是一个嵌套. .nav是的.active状态，其父母也将是.active状态。滚动导航栏旁边的区域，并观看活动班级更改，如下例：

Item 1

Ex consequat commodo adipisicing exercitation aute excepteur occaecat ullamco duis aliqua id magna ullamco eu. Do aute ipsum ipsum ullamco cillum consectetur ut et aute consectetur labore. Fugiat laborum incididunt tempor eu consequat enim dolore proident. Qui laborum do non excepteur nulla magna eiusmod consectetur in. Aliqua et aliqua officia quis et incididunt voluptate non anim reprehenderit adipisicing dolore ut consequat deserunt mollit dolore. Aliquip nulla enim veniam non fugiat id cupidatat nulla elit cupidatat commodo velit ut eiusmod cupidatat elit dolore.

Item 1-1

Amet tempor mollit aliquip pariatur excepteur commodo do ea cillum commodo Lorem et occaecat elit qui et. Aliquip labore ex ex esse voluptate occaecat Lorem ullamco deserunt. Aliqua cillum excepteur irure consequat id quis ea. Sit proident ullamco aute magna pariatur nostrud labore. Reprehenderit aliqua commodo eiusmod aliquip est do duis amet proident magna consectetur consequat eu commodo fugiat non quis. Enim aliquip exercitation ullamco adipisicing voluptate excepteur minim exercitation minim minim commodo adipisicing exercitation officia nisi adipisicing. Anim id duis qui consequat labore adipisicing sint dolor elit cillum anim et fugiat.

Item 2-2

Cillum nisi deserunt magna eiusmod qui eiusmod velit voluptate pariatur laborum sunt enim. Irure laboris mollit consequat incididunt sint et culpa culpa incididunt adipisicing magna magna occaecat. Nulla ipsum cillum eiusmod sint elit excepteur ea labore enim consectetur in labore anim. Proident ullamco ipsum esse elit ut Lorem eiusmod dolor et eiusmod. Anim occaecat nulla in non consequat eiusmod velit incididunt.

Item 2

Quis magna Lorem anim amet ipsum do mollit sit cillum voluptate ex nulla tempor. Laborum consequat non elit enim exercitation cillum aliqua consequat id aliqua. Esse ex consectetur mollit voluptate est in duis laboris ad sit ipsum anim Lorem. Incididunt veniam velit elit elit veniam Lorem aliqua quis ullamco deserunt sit enim elit aliqua esse irure. Laborum nisi sit est tempor laborum mollit labore officia laborum excepteur commodo non commodo dolor excepteur commodo. Ipsum fugiat ex est consectetur ipsum commodo tempor sunt in proident.

Item 3

Quis anim sit do amet fugiat dolor velit sit ea ea do reprehenderit culpa duis. Nostrud aliqua ipsum fugiat minim proident occaecat excepteur aliquip culpa aute tempor reprehenderit. Deserunt tempor mollit elit ex pariatur dolore velit fugiat mollit culpa irure ullamco est ex ullamco excepteur.

Item 3-1

Deserunt quis elit Lorem eiusmod amet enim enim amet minim Lorem proident nostrud. Ea id dolore anim exercitation aute fugiat labore voluptate cillum do laboris labore. Ex velit exercitation nisi enim labore reprehenderit labore nostrud ut ut. Esse officia sunt duis aliquip ullamco tempor eiusmod deserunt irure nostrud irure. Ullamco proident veniam laboris ea consectetur magna sunt ex exercitation aliquip minim enim culpa occaecat exercitation. Est tempor excepteur aliquip laborum consequat do deserunt laborum esse eiusmod irure proident ipsum esse qui.

Item 3-2

Labore sit culpa commodo elit adipisicing sit aliquip elit proident voluptate minim mollit nostrud aute reprehenderit do. Mollit excepteur eu Lorem ipsum anim commodo sint labore Lorem in exercitation velit incididunt. Occaecat consectetur nisi in occaecat proident minim enim sunt reprehenderit exercitation cupidatat et do officia. Aliquip consequat ad labore labore mollit ut amet. Sit pariatur tempor proident in veniam culpa aliqua excepteur elit magna fugiat eiusmod amet officia.

<nav id="navbar-example3" class="navbar navbar-light bg-light">
  <a class="navbar-brand" href="#">Navbar</a>
  <nav class="nav nav-pills flex-column">
    <a class="nav-link" href="#item-1">Item 1</a>
    <nav class="nav nav-pills flex-column">
      <a class="nav-link ml-3 my-1" href="#item-1-1">Item 1-1</a>
      <a class="nav-link ml-3 my-1" href="#item-1-2">Item 1-2</a>
    </nav>
    <a class="nav-link" href="#item-2">Item2</a>
    <a class="nav-link" href="#item-3">Item3</a>
    <nav class="nav nav-pills flex-column">
      <a class="nav-link ml-3 my-1" href="#item-3-1">Item 3-1</a>
      <a class="nav-link ml-3 my-1" href="#item-3-2">Item 3-2</a>
    </nav>
  </nav>
</nav>

<div data-spy="scroll" data-target="#navbar-example3" data-offset="0">
  <h4 id="item-1">Item 1</h4>
  <p>...</p>
  <h5 id="item-1-1">Item 1-1</h5>
  <p>...</p>
  <h5 id="item-1-2">Item 2-2</h5>
  <p>...</p>
  <h4 id="item-2">Item 2</h4>
  <p>...</p>
  <h4 id="item-3">Item 3</h4>
  <p>...</p>
  <h5 id="item-3-1">Item 3-1</h5>
  <p>...</p>
  <h5 id="item-3-2">Item 3-2</h5>
  <p>...</p>
</div>

列表组示例

Scrollspy 滚动监听也适用于 .list-group列表组，请滚动列表组旁边的区域，观看活动列表的变更：

Item 1 Item2 Item 3 Item 4

Item 1

Item 2

Item 3

Item 4

<div id="list-example" class="list-group">
  <a class="list-group-item list-group-item-action" href="#list-item-1">Item 1</a>
  <a class="list-group-item list-group-item-action" href="#list-item-2">Item2</a>
  <a class="list-group-item list-group-item-action" href="#list-item-3">Item 3</a>
  <a class="list-group-item list-group-item-action" href="#list-item-4">Item 4</a>
</div>
<div data-spy="scroll" data-target="#list-example" data-offset="0" class="scrollspy-example">
  <h4 id="list-item-1">Item 1</h4>
  <p>...</p>
  <h4 id="list-item-2">Item 2</h4>
  <p>...</p>
  <h4 id="list-item-3">Item 3</h4>
  <p>...</p>
  <h4 id="list-item-4">Item 4</h4>
  <p>...</p>
</div>

用法

通过数据属性

要轻松添加滚动行为到您的顶栏导航，添加 data-spy="scroll"到您要窥探的元素（通常是<body>）。然后添加data-target属性到任何Bootstrap .nav组件的父元素ID或类的Class属性。

body {
  position: relative;
}

<body data-spy="scroll" data-target="#navbar-example">
  ...
  <div id="navbar-example">
    <ul class="nav nav-tabs" role="tablist">
      ...
    </ul>
  </div>
  ...
</body>

通过 JavaScript

在你的CSS加上 position: relative; ，通过JavaScript调用滚动监控:

$('body').scrollspy({ target: '#navbar-example' })

需要可分辨（明确）的ID目标

Navbar links must have resolvable id targets. For example, a <a href="#home">home</a> must correspond to something in the DOM like <div id="home"></div>.

忽略非`:visible` 目标元素

目标元素如果是非 :visible ，在jQuery中将被忽略，其它相对应的导航组永远不会被突出显示。

方法

`.scrollspy('refresh')`

当从DOM加入或删除元素使用滚动监控时，你需要调用刷新方式，如下所示：

$('[data-spy="scroll"]').each(function () {
  var $spy = $(this).scrollspy('refresh')
})

`.scrollspy('dispose')`

销毁一个滚动元素。

选项

选项可以通过数据属性或JavaScript传递。对于数据属性，请将选项名称附加到 data-,如 data-offset=""。

名称	Type类型	默认值	描述
offset	number	10	计算滚动位置时，从顶部开始的计算的像偏移距离。

事件

Event事件类型	描述
activate.bs.scrollspy	每当新项目被滚动激活时，该事件就会在滚动元素上触发。

$('[data-spy="scroll"]').on('activate.bs.scrollspy', function () {
  // do something…
})

滚动监听(Scrollspy)

运行原理

在navbar导航中的示例

@fat

@mdo

one

two

three

嵌套的导航示例

Item 1

Item 1-1

Item 2-2

Item 2

Item 3

Item 3-1

Item 3-2

列表组示例

Item 1

Item 2

Item 3

Item 4

用法

通过数据属性

通过 JavaScript

需要可分辨（明确）的ID目标

忽略非:visible 目标元素

方法

.scrollspy('refresh')

.scrollspy('dispose')

选项

事件

忽略非`:visible` 目标元素

`.scrollspy('refresh')`

`.scrollspy('dispose')`