Session 09 - JavaScript, Part 2

Harvard University
Extension School

Course Web Site: http://cscie12.dce.harvard.edu

Instructor email: david_heitmeyer@harvard.edu
Course staff email: cscie12@dce.harvard.edu

Topics

  1. JavaScript - Minifying and CDNs
  2. jQuery Examples
  3. Add Another
  4. Unobtrusive Javascript / Progressive Enhancement
  5. jQuery UI
  6. Slideshow
  7. Form Validation
  8. Javascript Helping with Navigation

slide1 slide2 slide3 slide4 slide5 slide6 slide7 slide8 slide9 slide10 slide11 slide12 slide13 slide14 slide15 slide16 slide17 slide18 slide19 slide20 slide21 slide22 slide23 slide24 slide25 slide26 slide27 slide28 slide29 slide30 

JavaScript - Minifying and CDNs

Minified JS

Comments and unnecessary whitespace are removed.

Minify Your JS (and CSS)

Some tools you can use to minify your JS:

Load Your Core JS Library through a CDN

CDN - What and Why

CDN = Content Delivery Network

See: 3 reasons why you should let Google host jQuery for you (or any other CDN)

cdn

maxcdn

CDNs to Use

See: Using jQuery with a CDN

But not just jQuery! MaxCDN, Google, Microsoft, and cdnjs.com host several JS libraries through their CDNs:

jQuery Examples

Ice Cream

Let's see how we can do this with jQuery. Items to note:

Example 9.1 - Separation from Markup - Example 9.1 (Without Styles) | Example 9.1 JSFiddle
<form method="get" name="ice_cream" id="ice_cream" action="http://cscie12.dce.harvard.edu/echo">
<div>Would you like ice cream?<br/>
<input type="radio" name="want" id="ic_yes" value="yes"/><label for="ic_yes">Yes</label><br/>
<input type="radio" name="want" id="ic_no" value="no"/><label for="ic_no">No</label></div><fieldset id="icecream_options"><legend>Ice Cream Options</legend><p>How would you like it?</p>

<input type="radio" id="container_cup" name="container" value="cup"/><label for="container_cup">Cup</label><br/>
<input type="radio" id="container_cone" name="container" value="cone"/><label for="container_cone">Cone</label><br/><p>Pick your toppings:</p>

<input type="checkbox" name="toppings" id="toppings_wc" value="whipcream"/><label for="toppings_wc">Whipped cream</label><br/>
<input type="checkbox" name="toppings" id="toppings_j" value="jimmies"/><label for="toppings_j">Jimmies</label><br/>
<input type="checkbox" name="toppings" id="toppings_nuts" value="nuts"/><label for="toppings_nuts">Nuts</label><br/>
<input type="checkbox" name="toppings" id="toppings_cherry" value="cherry"/><label for="toppings_cherry">Cherry</label></fieldset><p>
<input type="submit"/></p>

</form>
   

In style element (<style type="text/css">) within head element:

#icecream_options { 
    background-color: #eee;
    margin-left: 2em;
}

In script element within head element (<script type="text/javascript">):

$(document).ready(function(){
    $("#icecream_options").hide();
    $("input[name='want']").click(function(){
      displayIceCreamOptions();
    });
});
function displayIceCreamOptions() {
    if ($("input[name='want']:checked").val() == 'yes') {
      $('#icecream_options').fadeIn('slow');
    } else {
      $('#icecream_options').fadeOut('slow');
    }
}
 

ice cream options

ice cream options

ice cream options

Check and Uncheck All

JavaScript:

Here we take advantage of an attribute value selector ([name="how"]) the ability to retrieve and set property values. Note too that we iterate through each of the checkboxes.

To read more about attributes vs properties in jQuery, see: .prop() and .attr()

Example 9.2 - Check/Uncheck all - Example 9.2 | Example 9.2 JSFiddle
<form action="http://cscie12.dce.harvard.edu/echo" method="get">
<h3>How did you hear about us?</h3><p>[<a href="#" id="checkall">check all</a>] [<a href="#" id="uncheckall">uncheck all</a>] [<a href="#" id="togglecheckboxes">toggle</a>]</p>
<ul style="list-style: none;">
<li>
<input type="checkbox" name="how" value="radio"/>Radio</li>
<li>
<input type="checkbox" name="how" value="newspaper"/>Newspaper</li>
<li>
<input type="checkbox" name="how" value="magazine"/>Magazine</li>
<li>
<input type="checkbox" name="how" value="online"/>Online</li>
<li>
<input type="checkbox" name="how" value="friend"/>Friend</li>
</ul>
<input type="submit"/>
</form>
 

In script element within head element (<script type="text/javascript">):

$(document).ready(function() {
  console.log($('#input[name="how"]'));
  $('#checkall').click(function() {
    $('input[name="how"]').prop('checked',true);
    console.log('check all!');
  });
  $('#uncheckall').click(function() {
    $('input[name="how"]').prop('checked',false);
    console.log('uncheck all!');
  });
  $('#togglecheckboxes').click(function() {
    $('input[name=how]').each(function (i) {
      if ($(this).is(':checked')) {
        $(this).prop('checked',false);
      } else {
        $(this).prop('checked',true);
      }     
    });
  });
 });
 

check all

Add Another

Example: add_another.html | Add Another in JSFiddle

add another

JavaScript:

$(document).ready(function() {
    var numberofphones = 1;
    $('#addphone').click(function() {
      numberofphones++;
      newid = 'phone' + numberofphones;
      var phonediv = $('#phone1');
      var newphonediv = phonediv.clone();
      newphonediv.attr('id',newid);
      newphonediv.insertBefore('#addphone');
  });
 });

Markup:

<form action="http://cscie12.dce.harvard.edu/echo" method="get">
  <fieldset>
    <legend>Contact Information</legend>
    <div>Name:  
      <input type="text" name="name"/></div>
    <div id="phone1">Phone:  
      <input type="text" name="phone"/> </div>
      <input type="button" id="addphone" value="Add another phone"/>
  </fieldset>
  <div><input type="submit"/></div>
</form>

Chaining jQuery

jQuery methods return nodes, so we can easily chain these steps together.

Stepwise:

$(document).ready(function() {
    var numberofphones = 1;
    $('#addphone').click(function() {
      numberofphones++;
      newid = 'phone' + numberofphones;
      var phonediv = $('#phone1');
      var newphonediv = phonediv.clone();
      newphonediv.attr('id',newid);
      newphonediv.insertBefore('#addphone');
  });
 });

Chained:

$(document).ready(function() {
    var numberofphones = 1;
    $('#addphone').click(function() {
      numberofphones++;
      newid = 'phone' + numberofphones;
      $('#phone1').clone().attr('id',newid).insertBefore('#addphone');
  });
 });

Unobtrusive Javascript / Progressive Enhancement

Principles of Unobtrusive JavaScript

Progressive Enhancement for "add another"

$(document).ready(function() {
  $('#addphone').css('display','inline');
  var numberofphones = 1;
  $('#addphone').click(function() {
      numberofphones++;
      newid = 'phone' + numberofphones;
      $('#phone1').clone().attr('id',newid).insertBefore('#addphone');
  });
 });

A browser with JS disabled would display form with a single phone field.

Example: add_another_unobtrusive.html
With JavaScript disabled in browser:
add another

Ice Cream

Start with everything visible, then hide with JavaScript:
Key piece here is: $("#icecream_options").hide();

Example 9.3 - Separation from Markup - Example 9.3 (Without Styles) |
<form method="get" name="ice_cream" id="ice_cream" action="http://cscie12.dce.harvard.edu/echo">
<div>Would you like ice cream?<br/>
<input type="radio" name="want" id="ic_yes" value="yes"/><label for="ic_yes">Yes</label><br/>
<input type="radio" name="want" id="ic_no" value="no"/><label for="ic_no">No</label></div><fieldset id="icecream_options"><legend>Ice Cream Options</legend><p>How would you like it?</p>

<input type="radio" id="container_cup" name="container" value="cup"/><label for="container_cup">Cup</label><br/>
<input type="radio" id="container_cone" name="container" value="cone"/><label for="container_cone">Cone</label><br/><p>Pick your toppings:</p>

<input type="checkbox" name="toppings" id="toppings_wc" value="whipcream"/><label for="toppings_wc">Whipped cream</label><br/>
<input type="checkbox" name="toppings" id="toppings_j" value="jimmies"/><label for="toppings_j">Jimmies</label><br/>
<input type="checkbox" name="toppings" id="toppings_nuts" value="nuts"/><label for="toppings_nuts">Nuts</label><br/>
<input type="checkbox" name="toppings" id="toppings_cherry" value="cherry"/><label for="toppings_cherry">Cherry</label></fieldset><p>
<input type="submit"/></p>

</form>
   

In style element (<style type="text/css">) within head element:

#icecream_options { 
    background-color: #eee;
    margin-left: 2em;
}

In script element within head element (<script type="text/javascript">):

$(document).ready(function(){
    $("#icecream_options").hide();
    $("input[name='want']").click(function(){
      displayIceCreamOptions();
    });
});
function displayIceCreamOptions() {
    if ($("input[name='want']:checked").val() == 'yes') {
      $('#icecream_options').fadeIn('slow');
    } else {
      $('#icecream_options').fadeOut('slow');
    }
}
 

ice cream options

ice cream options

What's the difference between sprinkles and jimmies?

jQuery UI

jQuery UI is a curated set of user interface interactions, effects, widgets, and themes built on top of the jQuery JavaScript Library. Whether you're building highly interactive web applications or you just need to add a date picker to a form control, jQuery UI is the perfect choice.

jquery ui

Tabs with jQuery

jQuery UI Tab Widget allows the easy creation of tabs from simple markup.

With JS and CSS:
tabs

Without JS and CSS:
tabs

Markup:

<div id="tabs">
    <ul>
      <li><a href="#basic">Overview</a>
      </li>

      <li><a href="#description">Description</a>
      </li>
      <li><a href="#schedule">Schedule</a>
      </li>
    </ul>
    
    <div id="basic">
      <h2>Overview</h2>
      <h3>Fundamentals of Website Development
        <br/>CSCI E-12</h3>
      <p>Harvard Extension School</p>
      <p><a href="http://cscie12.dce.harvard.edu/">cscie12.dce.harvard.edu</a>
        </p>
    </div>
    
    <div id="description">
      <h2>Course Description</h2>
      <p>This course provides a comprehensive overview of website development. Students explore the prevailing vocabulary, tools, and standards used in the field and learn how the various facets including HTML5, XHTML, CSS, JavaScript, Ajax, multimedia, scripting languages, HTTP, clients, servers, and databases function together in today's web environment. The course provides a solid web development foundation, focusing on content and client-side (browser) components (HTML5, XHTML, CSS, JavaScript, multimedia), with an overview of the server-side technologies. In addition, software and services that are easily incorporated into a website (for example, maps, checkout, blogs, content management) are surveyed and discussed. Students produce an interactive website on the topic of their choice for the final project and leave the course prepared for more advanced and focused web development studies.    </div>
    
    <div id="schedule">
      <h2>Schedule of Lectures</h2>

      <ol>
        <li>Introduction, Internet and Web Basics</li>
        <li>Markup: XHTML and HTML, Part 1</li>
        <li>Markup: XHTML and HTML, Part 2</li>
        <li>Style: Cascading Style Sheets (CSS), Part 1</li>
        <li>Style: Cascading Style Sheets (CSS), Part 2</li>
        <li>Style: CSS, Part 3</li>
        <li>Designing and Building a Site</li>
        <li>Function: Javascript, Part 1</li>
        <li>Function: JavaScript and Ajax, Part 2</li>
        <li>Function: External Functionality, Flash, Applets, and Web 2.0</li>
        <li>Video and Multimedia on the Web</li>
        <li>Server-side: Dynamic content</li>
        <li>Server-side: HTTP and Apache Web Server</li>
        <li>Grab Bag</li>
      </ol>
    </div>
  </div>

JS and CSS:

<link rel="stylesheet" 
  href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.11.4/themes/sunny/jquery-ui.css" 
  type="text/css" media="all" />
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.12.2/jquery.min.js"
    type="text/javascript"></script>
<script
    src="http://ajax.googleapis.com/ajax/libs/jqueryui/1.11.4/jquery-ui.min.js"
    type="text/javascript"></script>
<script type="text/javascript">
  $(function(){
    $('#tabs').tabs();
  });
</script>

jQuery UI Tabs: NOT for site navigation!

Wrong Way

jQuery UI Tabs: Featured Content Slider

Featured content slider using jQuery UI

featured content hot dogs

Javascript: (just like any other jQuery UI Tabs:

$(document).ready(function(){
     $("#featured").tabs({fx:{opacity: "toggle"}}).tabs("rotate", 5000, true);
});

Markup:

<div id="featured" >
  <div id="fragment-1"> <img src="images/featured1.jpg"  />
    <div class="info" >...</div>
  </div>
  <div id="fragment-2"> <img src="images/featured2.jpg"  />
    <div class="info" >...</div>
  </div>
  <div id="fragment-3"> <img src="images/featured3.jpg"  />
    <div class="info" >...</div>
  </div>
  <!-- ... -->
  <div id="fragment-7"> <img src="images/featured7.jpg"  />
    <div class="info" >...</div>
  </div>
  <ul class="ui-tabs-nav">
    <li id="nav-fragment-1"><a href="#fragment-1"><img src="thumbnail1.jpg"/></a></li>
    <li id="nav-fragment-2"><a href="#fragment-2"><img src="thumbnail2.jpg"/></a></li>
    <li id="nav-fragment-3"><a href="#fragment-3"><img src="thumbnail3.jpg"/></a></li>
    <!-- ... -->
    <li id="nav-fragment-7"><a href="#fragment-3"><img src="thumbnail7.jpg"/></a></li>
  </ul>
</div>

Rotating Carousels

Harvard - Carousel to No Carousel

Carousel:
harvard carousel

No Carousel:
harvard no carousel

Other jQuery UI Widgets

jQuery UI is a curated set of user interface interactions, effects, widgets, and themes built on top of the jQuery JavaScript Library. Whether you're building highly interactive web applications or you just need to add a date picker to a form control, jQuery UI is the perfect choice.

jQuery UI provides abstractions for low-level interaction and animation, advanced effects and high-level, themeable widgets, built on top of the jQuery JavaScript Library, that you can use to build highly interactive web applications.

jQuery Datepicker Widget

jQuery has plugins that will provide an unobtrusive "calendar" widget for picking dates.
datepicker

Example: date_picker.html

Markup:

<form action="http://cscie12.dce.harvard.edu/echo">
  <p>
    Enter a start date: <input class="date" type="text" size="32" name="startdate" id="startdate" />
  </p>
  <p>
    Enter an end date: <input class="date" type="text" size="32" name="enddate" id="enddate" />
  </p>
  <input type="submit"/>
</form>

CSS amd JS:

<link rel="stylesheet" 
  href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.10.4/themes/smoothness/jquery-ui.css" 
  type="text/css" media="all" />
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.12.2/jquery.min.js"
    type="text/javascript"></script>
<script
    src="http://ajax.googleapis.com/ajax/libs/jqueryui/1.11.4/jquery-ui.min.js"
    type="text/javascript"></script>
<script type="text/javascript">
  $(document).ready(function(){
    $('input.date').datepicker();
  })
</script>

jQuery UI Themes

Apply the "smoothness" theme
(css/smoothness/jquery-ui-1.10.4.custom.css):
datepicker

Apply the "hot-sneaks" theme
(css/hot-sneaks/jquery-ui-1.10.4.custom.css):
datepicker

Slideshow

Structure + Style + Function: solarsystem.html
markup

Structure + Style: solarsystem-style.html
markup

Slideshow

A gallery with no JavaScript -- thumbnail images are linked to the full-sized image with a simple
<a href="full/a.png" rel="gallery"><img src="thumb/a.png"/></a>:

unobtrusive

Example Galleries

View example galleries implemented in various "lightbox" or "slideshow" programs.

Colorboxgallerygallery
Fancyboxgallerygallery
Lightbox 2gallerygallery

Form Validation

jQuery Validation Plugin makes validating forms easy and flexible.

form

<html>
<head>
  <title>A Form to Illustrate Validation using the jQuery Validation Plugin</title>
  <link rel="stylesheet" type="text/css" href="form.css"/>
<script src="https://code.jquery.com/jquery-2.2.2.min.js"
    type="text/javascript"></script>
<script type="text/javascript"
    src="https://cdnjs.cloudflare.com/ajax/libs/jquery-validate/1.15.0/jquery.validate.min.js">
</script>
<script type="text/javascript">
$(document).ready(function(){
    $("#myForm").validate();
});
</script>
</head>
<body>
  <form  id="myForm" method="post"
    action="http://cscie12.dce.harvard.edu/echo">
    <fieldset>
      <legend>Information</legend>
      <p>
        <label for="name">Name</label> <em>(Required)</em>
        <br/>
        <input id="name" name="name" size="25" class="required"/> </p>
      <p>
        <label for="email">Email Address</label> <em>(Required)</em>
        <br/>
        <input id="email" name="email" size="25" class="required email"/> </p>
      <p>
        <label for="url">URL</label> <em>(Required)</em>
        <br/>
        <input id="url" name="url" size="25" class="required url"/> </p>
      <p>
        <input class="submit" type="submit" value="Submit Form"/> </p>
    </fieldset>
  </form>
</body>
</html>

Form Validation

Rules are quite customizable and can be expressed in JavaScript sections and not in the code markup.

form validation

<html>
<head>
  <title>A Form to Illustrate Validation using the jQuery Validation Plugin</title>
  <link rel="stylesheet" type="text/css" href="form.css"/>
<script src="https://code.jquery.com/jquery-2.2.2.min.js"
    type="text/javascript"></script>
<script type="text/javascript"
    src="https://cdnjs.cloudflare.com/ajax/libs/jquery-validate/1.15.0/jquery.validate.min.js">
</script>
<script type="text/javascript">
$(document).ready(function(){
  var validation = $("#myForm").validate(
    {
    rules: { 
      name:  { required: true, minlength: 2 },
      email: { required: true, email: true },
      url:   { required: true, url: true }
    }
  });
});
</script>
</head>
<body>
<form id="myForm" method="post" action="http://cscie12.dce.harvard.edu/echo">
<fieldset>
   <legend>A Form to Illustrate Validation using the jQuery Validation Plugin</legend>
   <p>
     <label for="name">Name</label><br/>
     <input id="name" name="name" size="25"/>
   </p>
   <p>
     <label for="email">Email Address</label><br/>
     <input id="email" name="email" size="25"/>
   </p>
   <p>
     <label for="url">URL</label><br/>
     <input id="url" name="url" size="25"  value="" />
   </p>
 <p>
     <input class="submit" type="submit" value="Submit"/>
   </p>
 </fieldset>
 </form>
</body>
</html>

Form Validation

form validation

  $(document).ready(function(){
    var validation = $("#myForm").validate(
     {
       rules: { 
         name: { required: true, minlength: 2 },
         email: { required: true, email: true },
         url: { required: true, url: true },
         favnum: { required: true, number: true },
         favnum10: { required: true, number: true, min: 1, max: 10},
         color: {required: true},
         season: {required: true, minlength: 2},
         yourdate: { required: true, date: true }
       },
       messages: {
              season: { minlength: jQuery.validator.format("Pick a minimum of {0} choices") }
       },
       errorPlacement: function(error,element) {
           if ( element.is("[name=color]") ) 
              error.appendTo( $('p#color') );
           else if ( element.is("[name=season]") ) 
              error.appendTo( $('p#season') );
           else 
              error.insertAfter(element);
       }
     });
  });

Javascript Helping with Navigation

navigation

Navigation

Iroquois Constitution

<html>
  <head>
    <title>The Great Binding Law, Gayanashagowa (Constitution of the Iroquois Nations)</title>
    <link rel="stylesheet" type="text/css" href="style.css" /> 
  </head>
  <body id="part1">
    <?php include("inc/header.php"); ?>
    <?php include("inc/nav.php"); ?>
    <div id="main">
      <?php include("inc/content1.php"); ?>
    </div>
    <?php include("inc/footer.php"); ?>
  </body>
</html>

"You are here" with CSS

"You are Here" CSS Example in JSFiddle

you are here

<div id="navigation">
<ul id="mainnav">
<li id="navpart1"><a href="1.shtml">The Great Binding Law, Gayanashagowa</a></li>
<li id="navpart2"><a href="2.shtml">Rights, Duties and Qualifications of Lords</a></li>
<li id="navpart3"><a href="3.shtml">Election of Pine Tree Chiefs</a></li>
<li id="navpart4"><a href="4.shtml">Names, Duties and Rights of War Chiefs</a></li>
<li id="navpart5"><a href="5.shtml">Clans and Consanguinity</a></li>
<li id="navpart6"><a href="6.shtml">Official Symbolism</a></li>
<li id="navpart7"><a href="7.shtml">Laws of Adoption</a></li>
<li id="navpart8"><a href="8.shtml">Laws of Emigration</a></li>
<li id="navpart9"><a href="9.shtml">Rights of Foreign Nations</a></li>
<li id="navpart10"><a href="10.shtml">Rights and Powers of War</a></li>
<li id="navpart11"><a href="11.shtml">Treason or Secession of a Nation</a></li>
<li id="navpart12"><a href="12.shtml">Rights of the People of the Five Nations</a></li>
<li id="navpart13"><a href="13.shtml">Religious Ceremonies Protected</a></li>
<li id="navpart14"><a href="14.shtml">The Installation Song</a></li>
<li id="navpart15"><a href="15.shtml">Protection of the House</a></li>
<li id="navpart16"><a href="16.shtml">Funeral Addresses</a></li>
</ul>
</div>

And the CSS:

#navigation a {
  /* Rules for navigation items */
}
#navigation a:hover {
  /* Rules for navigation items */
}  

/* Rules specific for "you are here" */
#navigation #iamhere a, 
#navigation #iamhere a:hover {
  /* Rules for the "you are here" item */
}

"You are here" with JavaScript

View this technique in action.Example in JSFiddle

  1. Each body is uniquely identified (id)
  2. Each navigation list item gets an id
  3. CSS rule for id="iamhere"
  4. JavaScript to set the "iamhere" id

Note the id of the body:

<html>
<head>
    <title>Election of Pine Tree Chiefs (Constitution of the Iroquois Nations)</title>
    <link rel="stylesheet" type="text/css" href="style.css" /> 
  </head>
  <body id="part3">
    <?php include("inc/header.php"); ?>
    <?php include("inc/nav.php"); ?>
    <div id="main">
      <?php include("inc/content3.php"); ?>
    </div>
    <?php include("inc/footer.php"); ?>
  </body>
</html>

Each navigation item has an id:

<div id="navigation">
<ul id="mainnav">
<li id="navpart1"><a href="1.shtml">The Great Binding Law, Gayanashagowa</a></li>
<li id="navpart2"><a href="2.shtml">Rights, Duties and Qualifications of Lords</a></li>
<li id="navpart3"><a href="3.shtml">Election of Pine Tree Chiefs</a></li>
<li id="navpart4"><a href="4.shtml">Names, Duties and Rights of War Chiefs</a></li>
<li id="navpart5"><a href="5.shtml">Clans and Consanguinity</a></li>
<li id="navpart6"><a href="6.shtml">Official Symbolism</a></li>
<li id="navpart7"><a href="7.shtml">Laws of Adoption</a></li>
<li id="navpart8"><a href="8.shtml">Laws of Emigration</a></li>
<li id="navpart9"><a href="9.shtml">Rights of Foreign Nations</a></li>
<li id="navpart10"><a href="10.shtml">Rights and Powers of War</a></li>
<li id="navpart11"><a href="11.shtml">Treason or Secession of a Nation</a></li>
<li id="navpart12"><a href="12.shtml">Rights of the People of the Five Nations</a></li>
<li id="navpart13"><a href="13.shtml">Religious Ceremonies Protected</a></li>
<li id="navpart14"><a href="14.shtml">The Installation Song</a></li>
<li id="navpart15"><a href="15.shtml">Protection of the House</a></li>
<li id="navpart16"><a href="16.shtml">Funeral Addresses</a></li>
</ul>
</div>

And the CSS:

#navigation a {
  /* Rules for navigation items */
}
#navigation a:hover {
  /* Rules for navigation items */
}  

/* Rules specific for "you are here" */
#navigation #iamhere a, 
#navigation #iamhere a:hover {
  /* Rules for the "you are here" item */
}

And the JavaScript (using jQuery) that finds the correct navigation item and sets the id attribute value to "iamhere":

$(document).ready(function(){
  var mybodyid = $('body').attr('id');
  var mynavid = '#nav' + mybodyid;
  /* e.g. for 3.shtml:
      mybodyid is 'part3'
      mynavid  is '#navpart3'
   */
  $(mynavid).attr('id','iamhere');
});

Pages from Parts and Clamshell Navigation

clamshell

<script type="text/javascript">
$(document).ready(function(){
  console.log("Ready!");
  var mybodyid = $('body').attr('id');
  var mynavid = '#nav_' + mybodyid;
  console.log("mybodyid is " + mybodyid);
  console.log("mynavid is " + mynavid);
  // Set iamhere id
  $(mynavid).attr('id','iamhere');
  // hide all nested lists
  $('#navigation ul ul').hide();
    // show parents of "iamhere"
  $('#iamhere').parents().show();
  // show children of "iamhere"
  $('#iamhere').children().show();
});
</script> 

JSFiddle Example

Note for the JSFiddle example, we are using a 'div' to contain the 'id' instead of the 'body'.
Clamshell Navigation in JS Fiddle

Files

Copyright © David Heitmeyer