http://www.madskillsbmx.com/js/rwd-nav.js

1/* Sample scripts for RWD nav patterns 
2   (c) 2012 Maggie Wachs, Filament Group, Inc - http://filamentgroup.com/examples/rwd-nav-patterns/GPL-LICENSE.txt
3   Last updated: March 2012
4   Dependencies: jQuery
5*/
6
7   
8
9jQuery(function($){
10
11   $('.nav-primary')
12      // test the menu to see if all items fit horizontally
13      .bind('testfit', function(){
14            var nav = $(this),
15                items = nav.find('a');
16                  
17            $('body').removeClass('nav-menu');                    
18                  
19            // when the nav wraps under the logo, or when options are stacked, display the nav as a menu              
20            if ( (nav.offset().top > nav.prev().offset().top) || ($(items[items.length-1]).offset().top > $(items[0]).offset().top) ) {
21            
22               // add a class for scoping menu styles
23               $('body').addClass('nav-menu');
24               
25            };                    
26         })
27      
28      // toggle the menu items' visiblity
29      .find('h3')
30         .bind('click focus', function(){
31            $(this).parent().toggleClass('expanded')
32         });   
33   
34   // ...and update the nav on window events
35   $(window).bind('load resize orientationchange', function(){
36      $('.nav-primary').trigger('testfit');
37   });
38
39});