/*!
 * jQuery hashchange event - v1.3 - 7/21/2010
 * http://benalman.com/projects/jquery-hashchange-plugin/
 * 
 * Copyright (c) 2010 "Cowboy" Ben Alman
 * Dual licensed under the MIT and GPL licenses.
 * http://benalman.com/about/license/
 */

// Script: jQuery hashchange event
//
// *Version: 1.3, Last updated: 7/21/2010*
// 
// Project Home - http://benalman.com/projects/jquery-hashchange-plugin/
// GitHub       - http://github.com/cowboy/jquery-hashchange/
// Source       - http://github.com/cowboy/jquery-hashchange/raw/master/jquery.ba-hashchange.js
// (Minified)   - http://github.com/cowboy/jquery-hashchange/raw/master/jquery.ba-hashchange.min.js (0.8kb gzipped)
// 
// About: License
// 
// Copyright (c) 2010 "Cowboy" Ben Alman,
// Dual licensed under the MIT and GPL licenses.
// http://benalman.com/about/license/
// 
// About: Examples
// 
// These working examples, complete with fully commented code, illustrate a few
// ways in which this plugin can be used.
// 
// hashchange event - http://benalman.com/code/projects/jquery-hashchange/examples/hashchange/
// document.domain - http://benalman.com/code/projects/jquery-hashchange/examples/document_domain/
// 
// About: Support and Testing
// 
// Information about what version or versions of jQuery this plugin has been
// tested with, what browsers it has been tested in, and where the unit tests
// reside (so you can test it yourself).
// 
// jQuery Versions - 1.2.6, 1.3.2, 1.4.1, 1.4.2
// Browsers Tested - Internet Explorer 6-8, Firefox 2-4, Chrome 5-6, Safari 3.2-5,
//                   Opera 9.6-10.60, iPhone 3.1, Android 1.6-2.2, BlackBerry 4.6-5.
// Unit Tests      - http://benalman.com/code/projects/jquery-hashchange/unit/
// 
// About: Known issues
// 
// While this jQuery hashchange event implementation is quite stable and
// robust, there are a few unfortunate browser bugs surrounding expected
// hashchange event-based behaviors, independent of any JavaScript
// window.onhashchange abstraction. See the following examples for more
// information:
// 
// Chrome: Back Button - http://benalman.com/code/projects/jquery-hashchange/examples/bug-chrome-back-button/
// Firefox: Remote XMLHttpRequest - http://benalman.com/code/projects/jquery-hashchange/examples/bug-firefox-remote-xhr/
// WebKit: Back Button in an Iframe - http://benalman.com/code/projects/jquery-hashchange/examples/bug-webkit-hash-iframe/
// Safari: Back Button from a different domain - http://benalman.com/code/projects/jquery-hashchange/examples/bug-safari-back-from-diff-domain/
// 
// Also note that should a browser natively support the window.onhashchange 
// event, but not report that it does, the fallback polling loop will be used.
// 
// About: Release History
// 
// 1.3   - (7/21/2010) Reorganized IE6/7 Iframe code to make it more
//         "removable" for mobile-only development. Added IE6/7 document.title
//         support. Attempted to make Iframe as hidden as possible by using
//         techniques from http://www.paciellogroup.com/blog/?p=604. Added 
//         support for the "shortcut" format $(window).hashchange( fn ) and
//         $(window).hashchange() like jQuery provides for built-in events.
//         Renamed jQuery.hashchangeDelay to <jQuery.fn.hashchange.delay> and
//         lowered its default value to 50. Added <jQuery.fn.hashchange.domain>
//         and <jQuery.fn.hashchange.src> properties plus document-domain.html
//         file to address access denied issues when setting document.domain in
//         IE6/7.
// 1.2   - (2/11/2010) Fixed a bug where coming back to a page using this plugin
//         from a page on another domain would cause an error in Safari 4. Also,
//         IE6/7 Iframe is now inserted after the body (this actually works),
//         which prevents the page from scrolling when the event is first bound.
//         Event can also now be bound before DOM ready, but it won't be usable
//         before then in IE6/7.
// 1.1   - (1/21/2010) Incorporated document.documentMode test to fix IE8 bug
//         where browser version is incorrectly reported as 8.0, despite
//         inclusion of the X-UA-Compatible IE=EmulateIE7 meta tag.
// 1.0   - (1/9/2010) Initial Release. Broke out the jQuery BBQ event.special
//         window.onhashchange functionality into a separate plugin for users
//         who want just the basic event & back button support, without all the
//         extra awesomeness that BBQ provides. This plugin will be included as
//         part of jQuery BBQ, but also be available separately.
 ( function( $, window, undefined )
 {
	'$:nomunge';
	// Used by YUI compressor.
	// Reused string.
	var str_hashchange = 'hashchange',

	// Method / object references.
	doc = document,
	fake_onhashchange,
	special = $.event.special,

	// Does the browser support window.onhashchange? Note that IE8 running in
	// IE7 compatibility mode reports true for 'onhashchange' in window, even
	// though the event isn't supported, so also test document.documentMode.
	doc_mode = doc.documentMode,
	supports_onhashchange = 'on' + str_hashchange in window && ( doc_mode === undefined || doc_mode > 7 );

	// Get location.hash (or what you'd expect location.hash to be) sans any
	// leading #. Thanks for making this necessary, Firefox!
	function get_fragment( url ) 
	{
		url = url || location.href;
		return '#' + url.replace( /^[^#]*#?(.*)$/, '$1' );
	};
	// Method: jQuery.fn.hashchange
	// 
	// Bind a handler to the window.onhashchange event or trigger all bound
	// window.onhashchange event handlers. This behavior is consistent with
	// jQuery's built-in event handlers.
	// 
	// Usage:
	// 
	// > jQuery(window).hashchange( [ handler ] );
	// 
	// Arguments:
	// 
	//  handler - (Function) Optional handler to be bound to the hashchange
	//    event. This is a "shortcut" for the more verbose form:
	//    jQuery(window).bind( 'hashchange', handler ). If handler is omitted,
	//    all bound window.onhashchange event handlers will be triggered. This
	//    is a shortcut for the more verbose
	//    jQuery(window).trigger( 'hashchange' ). These forms are described in
	//    the <hashchange event> section.
	//
	// Returns:
	// 
	//  (jQuery) The initial jQuery collection of elements.
	// Allow the "shortcut" format $(elem).hashchange( fn ) for binding and
	// $(elem).hashchange() for triggering, like jQuery does for built-in events.
	$.fn[ str_hashchange ] = function( fn ) 
	{
		return fn ? this.bind( str_hashchange, fn ) : this.trigger( str_hashchange );
	};

	// Property: jQuery.fn.hashchange.delay
	// 
	// The numeric interval (in milliseconds) at which the <hashchange event>
	// polling loop executes. Defaults to 50.
	// Property: jQuery.fn.hashchange.domain
	// 
	// If you're setting document.domain in your JavaScript, and you want hash
	// history to work in IE6/7, not only must this property be set, but you must
	// also set document.domain BEFORE jQuery is loaded into the page. This
	// property is only applicable if you are supporting IE6/7 (or IE8 operating
	// in "IE7 compatibility" mode).
	// 
	// In addition, the <jQuery.fn.hashchange.src> property must be set to the
	// path of the included "document-domain.html" file, which can be renamed or
	// modified if necessary (note that the document.domain specified must be the
	// same in both your main JavaScript as well as in this file).
	// 
	// Usage:
	// 
	// jQuery.fn.hashchange.domain = document.domain;
	// Property: jQuery.fn.hashchange.src
	// 
	// If, for some reason, you need to specify an Iframe src file (for example,
	// when setting document.domain as in <jQuery.fn.hashchange.domain>), you can
	// do so using this property. Note that when using this property, history
	// won't be recorded in IE6/7 until the Iframe src file loads. This property
	// is only applicable if you are supporting IE6/7 (or IE8 operating in "IE7
	// compatibility" mode).
	// 
	// Usage:
	// 
	// jQuery.fn.hashchange.src = 'path/to/file.html';
	$.fn[ str_hashchange ].delay = 50;
	/*
	$.fn[ str_hashchange ].domain = null;
	$.fn[ str_hashchange ].src = null;

	*/
	// Event: hashchange event
	// 
	// Fired when location.hash changes. In browsers that support it, the native
	// HTML5 window.onhashchange event is used, otherwise a polling loop is
	// initialized, running every <jQuery.fn.hashchange.delay> milliseconds to
	// see if the hash has changed. In IE6/7 (and IE8 operating in "IE7
	// compatibility" mode), a hidden Iframe is created to allow the back button
	// and hash-based history to work.
	// 
	// Usage as described in <jQuery.fn.hashchange>:
	// 
	// > // Bind an event handler.
	// > jQuery(window).hashchange( function(e) {
	// >   var hash = location.hash;
	// >   ...
	// > });
	// > 
	// > // Manually trigger the event handler.
	// > jQuery(window).hashchange();
	// 
	// A more verbose usage that allows for event namespacing:
	// 
	// > // Bind an event handler.
	// > jQuery(window).bind( 'hashchange', function(e) {	
	// >   var hash = location.hash;
	// >   ...
	// > });
	// > 
	// > // Manually trigger the event handler.
	// > jQuery(window).trigger( 'hashchange' );
	// 
	// Additional Notes:
	// 
	// * The polling loop and Iframe are not created until at least one handler
	//   is actually bound to the 'hashchange' event.
	// * If you need the bound handler(s) to execute immediately, in cases where
	//   a location.hash exists on page load, via bookmark or page refresh for
	//   example, use jQuery(window).hashchange() or the more verbose 
	//   jQuery(window).trigger( 'hashchange' ).
	// * The event can be bound before DOM ready, but since it won't be usable
	//   before then in IE6/7 (due to the necessary Iframe), recommended usage is
	//   to bind it inside a DOM ready handler.
	// Override existing $.event.special.hashchange methods (allowing this plugin
	// to be defined after jQuery BBQ in BBQ's source code).	
	special[ str_hashchange ] = $.extend( special[ str_hashchange ], 
	{

		// Called only when the first 'hashchange' event is bound to window.
		setup: function() 
		{
			// If window.onhashchange is supported natively, there's nothing to do..
				if ( supports_onhashchange ) 
				{
					return false;
				}
			// Otherwise, we need to create our own. And we don't want to call this
			// until the user binds to the event, just in case they never do, since it
			// will create a polling loop and possibly even a hidden Iframe.
			$( fake_onhashchange.start );
		},

		// Called only when the last 'hashchange' event is unbound from window.
		teardown: function() 
		{
			// If window.onhashchange is supported natively, there's nothing to do.
			if ( supports_onhashchange ) 
			{
				return false;
			}
			// Otherwise, we need to stop ours (if possible).
			$( fake_onhashchange.stop );
		}
	});
	// fake_onhashchange does all the work of triggering the window.onhashchange
	// event for browsers that don't natively support it, including creating a
	// polling loop to watch for hash changes and in IE 6/7 creating a hidden
	// Iframe to enable back and forward.
	fake_onhashchange = ( function()
	{
		var self = {},
		timeout_id,
		// Remember the initial hash so it doesn't get triggered immediately.
		last_hash = get_fragment(),
		fn_retval = function( val )
		{
			return val;
		},
		history_set = fn_retval,
		history_get = fn_retval;

		// Start the polling loop.
		self.start = function() 
		{
			timeout_id || poll();
		};

		// Stop the polling loop.
		self.stop = function() 
		{
			timeout_id && clearTimeout( timeout_id );
			timeout_id = undefined;
		};
		// This polling loop checks every $.fn.hashchange.delay milliseconds to see
		// if location.hash has changed, and triggers the 'hashchange' event on
		// window when necessary.
		function poll() 
		{
			var hash = get_fragment(),
			history_hash = history_get( last_hash );
			if ( hash !== last_hash ) 
			{
				history_set(last_hash = hash, history_hash);
				$(window).trigger(str_hashchange);
			} 
			else if ( history_hash !== last_hash ) 
			{
				location.href = location.href.replace( /#.*/, '' ) + history_hash;
			}
			timeout_id = setTimeout( poll, $.fn[ str_hashchange ].delay );
		};

		// vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
		// vvvvvvvvvvvvvvvvvvv REMOVE IF NOT SUPPORTING IE6/7/8 vvvvvvvvvvvvvvvvvvv
		// vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
		$.browser.msie && !supports_onhashchange && ( function()
		{
			// Not only do IE6/7 need the "magical" Iframe treatment, but so does IE8
			// when running in "IE7 compatibility" mode.
			var iframe,
			iframe_src;

			// When the event is bound and polling starts in IE 6/7, create a hidden
			// Iframe for history handling.
			self.start = function() 
			{
				if ( !iframe ) 
				{
					iframe_src = $.fn[ str_hashchange ].src;
					iframe_src = iframe_src && iframe_src + get_fragment();
					// Create hidden Iframe. Attempt to make Iframe as hidden as possible
					// by using techniques from http://www.paciellogroup.com/blog/?p=604.
					iframe = $( '<iframe tabindex="-1" title="empty"/>' ).hide()
					// When Iframe has completely loaded, initialize the history and
					// start polling.
					.one( 'load', function() 
					{
						iframe_src || history_set( get_fragment() );
						poll();
					})
					// Load Iframe src if specified, otherwise nothing.
					.attr( 'src', iframe_src || 'javascript:0' )
					// Append Iframe after the end of the body to prevent unnecessary
					// initial page scrolling (yes, this works).
					.insertAfter( 'body' )[ 0 ].contentWindow;

					// Whenever `document.title` changes, update the Iframe's title to
					// prettify the back/next history menu entries. Since IE sometimes
					// errors with "Unspecified error" the very first time this is set
					// (yes, very useful) wrap this with a try/catch block.
					doc.onpropertychange = function() 
					{
					try 
						{
							if ( event.propertyName === 'title' )
							{
								iframe.document.title = doc.title;
							}
						} catch( e ) {}
					};
				}
			};

			// Override the "stop" method since an IE6/7 Iframe was created. Even
			// if there are no longer any bound event handlers, the polling loop
			// is still necessary for back/next to work at all!
			self.stop = fn_retval;

			// Get history by looking at the hidden Iframe's location.hash.
			history_get = function() 
			{
				return get_fragment( iframe.location.href );
			};

			// Set a new history item by opening and then closing the Iframe
			// document, *then* setting its location.hash. If document.domain has
			// been set, update that as well.
			history_set = function( hash, history_hash ) 
			{
				var iframe_doc = iframe.document,
				domain = $.fn[ str_hashchange ].domain;

				if ( hash !== history_hash ) 
				{
					// Update Iframe with any initial `document.title` that might be set.
					iframe_doc.title = doc.title;

					// Opening the Iframe's document after it has been closed is what
					// actually adds a history entry.
					iframe_doc.open();
					// Set document.domain for the Iframe document as well, if necessary.
					domain && iframe_doc.write( '<script>document.domain="'  +  domain + '"</script>' );
					iframe_doc.close();
					// Update the Iframe's hash, for great justice.
					iframe.location.hash = hash;
				}
			};
		})();
		// ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
		// ^^^^^^^^^^^^^^^^^^^ REMOVE IF NOT SUPPORTING IE6/7/8 ^^^^^^^^^^^^^^^^^^^
		// ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
		return self;
		})();
})( jQuery, this );