/*!

 * 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);