本文主要来学习一下JavaScript插件--滚动监听。
1、案例
滚动监听插件可以根据滚动条的位置自动更新所对应的导航标记。你可以试试滚动这个页面，看看左侧导航的变化。
先把实现的代码上了，你可以通过测试代码先来看看效果。
<!DOCTYPE html>
<html>
<head>
<title>Bootstrap</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<!-- Bootstrap -->
<link href="css/bootstrap.min.css" rel="stylesheet" media="screen">
<!--[if lt IE 9]>
<script src="https://oss.maxcdn.com/libs/html5shiv/3.7.0/html5shiv.js">
</script>
<script src="https://oss.maxcdn.com/libs/respond.js/1.3.0/respond.min.js">
</script>
<![endif]-->
<style type="text/css"> .scrollspy-example
{
height: 200px;
overflow: auto;
position: relative;
border:1px solid red;
}
</style>
</head>
<body>
<div class="container" >
<nav id="navbar-example" class="navbar navbar-default navbar-static" role="navigation">
<div class="navbar-header">
<button class="navbar-toggle" type="button" data-toggle="collapse" data-target=".bs-js-navbar-scrollspy">
<span class="sr-only">Toggle navigation</span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</button>
<a class="navbar-brand" href="#">Project Name</a>
</div>
<div class="collapse navbar-collapse bs-js-navbar-scrollspy">
<ul class="nav navbar-nav">
<li class="active"><a href="#fat">@fat</a></li>
<li><a href="#mdo">@mdo</a></li>
<li class="dropdown">
<a href="#" id="navbarDrop1" class="dropdown-toggle" data-toggle="dropdown">Dropdown
<b class="caret"></b></a>
<ul class="dropdown-menu" role="menu" aria-labelledby="navbarDrop1">
<li><a href="#one" tabindex="-1">one</a></li>
<li><a href="#two" tabindex="-1">two</a></li>
<li class="divider"></li>
<li><a href="#three" tabindex="-1">three</a></li>
</ul>
</li>
</ul>
</div>
</nav>
<div data-offset="0" class="scrollspy-example" data-spy="scroll" data-target="#navbar-example">
<h4 id="fat">@fat</h4>
<p>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.</p>
<h4 id="mdo">@mdo</h4>
<p>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.</p> <h4 id="one">one</h4> <p>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.</p>
<h4 id="two">two</h4>
<p>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.</p>
<h4 id="three">three</h4>
<p>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.</p>
<p>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. </p>
</div>
</div>
<script src="js/jquery-2.0.3.min.js">
</script>
<script src="js/bootstrap.min.js">
</script>
</body>
</html>
用法1--通过data属性
通过为需要监听的页面元素（一般是）不过在上面添加在了Div上面，你可以自己看看代码就明白了。然后给div添加属性data-spy="scroll"就可很轻松的为顶部导航条添加滚动监听功能。然后为其添加data-target属性，此属性的值为任何Bootstrap中.nav组件的父元素的ID或class。