/public/jquery/event/hashchange/hashchange.js

/*!

 * jQuery hashchange event - v1.2 - 2/11/2010

 * 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: 1.2, Last updated: 2/11/2010*

// 

// 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 (1.1kb)

// 

// About: License

// 

// Copyright (c) 2010 "Cowboy" Ben Alman,

// Dual licensed under the MIT and GPL licenses.

// http://benalman.com/about/license/

// 

// About: Examples

// 

// This working example, complete with fully commented code, illustrate one way

// in which this plugin can be used.

// 

// hashchange event - http://benalman.com/code/projects/jquery-hashchange/examples/hashchange/

// 

// 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 2-3.7, Safari 3-4, Chrome, Opera 9.6-10.1.

// 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/

// 

// About: Release History

// 

// 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.

  

  // Method / object references.

  var fake_onhashchange,

    jq_event_special = $.event.special,

    

    // Reused strings.

    str_location = 'location',

    str_hashchange = 'hashchange',

    str_href = 'href',

    

    // IE6/7 specifically need some special love when it comes to back-button

    // support, so let's do a little browser sniffing..

    browser = $.browser,

    mode = document.documentMode,

    is_old_ie = browser.msie && ( mode === undefined || mode < 8 ),

    

    // Does the browser support window.onhashchange? Test for IE version, since

    // IE8 incorrectly reports this when in "IE7" or "IE8 Compatibility View"!

    supports_onhashchange = 'on' + str_hashchange in window && !is_old_ie;

  

  // 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 || window[ str_location ][ str_href ];

    return url.replace( /^[^#]*#?(.*)$/, '$1' );

  };

  

  // Property: jQuery.hashchangeDelay

  // 

  // The numeric interval (in milliseconds) at which the <hashchange event>

  // polling loop executes. Defaults to 100.

  

  $[ str_hashchange + 'Delay' ] = 100;

  

  // Event: hashchange event

  // 

  // Fired when location.hash changes. In browsers that support it, the native

  // window.onhashchange event is used (IE8, FF3.6), otherwise a polling loop is

  // initialized, running every <jQuery.hashchangeDelay> milliseconds to see if

  // the hash has changed. In IE 6 and 7, a hidden Iframe is created to allow

  // the back button and hash-based history to work.

  // 

  // Usage:

  // 

  // > $(window).bind( 'hashchange', function(e) {

  // >   var hash = location.hash;

  // >   ...

  // > });

  // 

  // Additional Notes:

  // 

  // * The polling loop and Iframe are not created until at least one callback

  //   is actually bound to 'hashchange'.

  // * If you need the bound callback(s) to execute immediately, in cases where

  //   the page 'state' exists on page load (via bookmark or page refresh, for

  //   example) use $(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 $(document).ready() callback.

  

  jq_event_special[ str_hashchange ] = $.extend( jq_event_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,

      iframe,

      set_history,

      get_history;

    

    // Initialize. In IE 6/7, creates a hidden Iframe for history handling.

    function init(){

      // Most browsers don't need special methods here..

      set_history = get_history = function(val){ return val; };

      

      // But IE6/7 do!

      if ( is_old_ie ) {

        

        // Create hidden Iframe after the end of the body to prevent initial

        // page load from scrolling unnecessarily.

        iframe = $('<iframe src="javascript:0"/>').hide().insertAfter( 'body' )[0].contentWindow;

        

        // Get history by looking at the hidden Iframe's location.hash.

        get_history = function() {

          return get_fragment( iframe.document[ str_location ][ str_href ] );

        };

        

        // Set a new history item by opening and then closing the Iframe

        // document, *then* setting its location.hash.

        set_history = function( hash, history_hash ) {

          if ( hash !== history_hash ) {

            var doc = iframe.document;

            doc.open().close();

            doc[ str_location ].hash = '#' + hash;

          }

        };

        

        // Set initial history.

        set_history( get_fragment() );

      }

    };

    

    // Start the polling loop.

    self.start = function() {

      // Polling loop is already running!

      if ( timeout_id ) { return; }

      

      // Remember the initial hash so it doesn't get triggered immediately.

      var last_hash = get_fragment();

      

      // Initialize if not yet initialized.

      set_history || init();

      

      // This polling loop checks every $.hashchangeDelay milliseconds to see if

      // location.hash has changed, and triggers the 'hashchange' event on

      // window when necessary.

      if(!navigator.userAgent.match(/Rhino/))

	      (function loopy(){

	        var hash = get_fragment(),

	          history_hash = get_history( last_hash );

	        

	        if ( hash !== last_hash ) {

	          set_history( last_hash = hash, history_hash );

	          

	          $(window).trigger( str_hashchange );

	          

	        } else if ( history_hash !== last_hash ) {

	          window[ str_location ][ str_href ] = window[ str_location ][ str_href ].replace( /#.*/, '' ) + '#' + history_hash;

	        }

	        

	        timeout_id = setTimeout( loopy, $[ str_hashchange + 'Delay' ] );

	      })();

    };

    

    // Stop the polling loop, but only if an IE6/7 Iframe wasn't created. In

    // that case, 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 = function() {

      if ( !iframe ) {

        timeout_id && clearTimeout( timeout_id );

        timeout_id = 0;

      }

    };

    

    return self;

  })();

  

})(jQuery,this);