172 The Scrollspy (auto updating nav) plugin allows you to target sections of the

Use Cases

172 The Scrollspy (auto updating nav) plugin allows you to target sections of the

page based on the scroll position. In its basic implementation, as you scroll, you can add.activeclasses to the navbar based on the scroll position.

If you want to include this plugin functionality individually, then you will need scrollspy.js. Else, as mentioned in the chapterBootstrap Plugins Overview, you can includebootstrap.jsor the minifiedbootstrap.min.js.

Usage

You can add scrollspy behavior to your topbar navigation:

 Via data attributes: adddata-spy="scroll"to the element you want to spy on (typically the body). Then add attributedata-targetwith the ID or class of the parent element of any Bootstrap.navcomponent. For this to work, you must have elements in the body of the page that have matching IDs of the links that you are spying on.

...

...

</ul>

</div>

...

</body>

 Via JavaScript: You can invoke the scrollspy with JavaScript instead of using the data attributes, by selecting the element to spy on, and then invoking the .scrollspy()function:

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

Example

The following example shows the use of scrollspy plugin via data attributes:

37. SCROLLSPY PLUGIN

173

<nav id="navbar-example" class="navbar navbar-default navbar-static"

role="navigation">

<button class="navbar-toggle" type="button" data-toggle="collapse"

data-target=".bs-js-navbar-scrollspy">

<span class="sr-only">Toggle navigation</span>

</button>

<a class="navbar-brand" href="#">Tutorial Name</a>

</div>

<div data-spy="scroll" data-target="#navbar-example" data-offset="0"

style="height:200px;overflow:auto; position: relative;">

174 <h4 id="ios">iOS</h4>

<p>iOS is a mobile operating system developed and distributed by Apple Inc. Originally released in 2007 for the iPhone, iPod Touch, and Apple TV. iOS is derived from OS X, with which it shares the Darwin

foundation. iOS is Apple's mobile version of the OS X operating system used on Apple computers.

</p>

<p>Apache Subversion which is often abbreviated as SVN, is a software versioning and revision control system distributed under an open source license. Subversion was created by CollabNet Inc. in 2000, but now it is developed as a project of the Apache Software Foundation, and as such is part of a rich community of developers and users.

</p>

<h4 id="jmeter">jMeter</h4>

<p>jMeter is an Open Source testing software. It is 100% pure Java application for load and performance testing.

</p>

<p>Enterprise Java Beans (EJB) is a development architecture for building highly scalable and robust enterprise level applications to be deployed on J2EE compliant Application Server such as JBOSS, Web Logic etc.

</p>

<h4 id="spring">Spring</h4>

<p>Spring framework is an open source Java platform that provides comprehensive infrastructure support for developing robust Java applications very easily and very rapidly.

</p>

<p>Spring framework was initially written by Rod Johnson and was first released under the Apache 2.0 license in June 2003.

</p>

</div>

175

Options

Options can be passed via data attributes or JavaScript. Following table lists the options:

data-offset Pixels to offset from top when calculating position of scroll.

Methods

.scrollspy('refresh'): When calling the scrollspy via the JavaScript method, you need to call the.refreshmethod to update the DOM. This is helpful if any elements of the DOM have changed i.e. if you have added or removed some elements. Following would be the syntax to use this method.

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

Example

The following example demonstrates the use of .scrollspy('refresh')method:

<nav id="myScrollspy" class="navbar navbar-default navbar-static"

role="navigation">

<button class="navbar-toggle" type="button" data-toggle="collapse"

data-target=".bs-js-navbar-scrollspy">

<span class="sr-only">Toggle navigation</span>

176 <span class="icon-bar"></span>

</button>

<a class="navbar-brand" href="#">Tutorial Name</a>

</div>

<div data-spy="scroll" data-target="#myScrollspy" data-offset="0"

style="height:200px;overflow:auto; position: relative;">

× Remove this section</a></small>

</h4>

<p>iOS is a mobile operating system developed and distributed by Apple Inc. Originally released in 2007 for the iPhone, iPod Touch, and

177

In document bootstrap_tutorial.pdf (Page 183-188)