ÿþ/*

* jQuery history plugin

*

* Copyright (c) 2006 Taku Sano (Mikage Sawatari)

* Licensed under the MIT License:

*   http://www.opensource.org/licenses/mit-license.php

*

* Modified by Lincoln Cooper to add Safari support and only call the callback once during initialization

* for msie when no initial hash supplied.

* API rewrite by Lauris Bukýÿis-Haberkorns

*/



(function($) {



    function History() {

        this._curHash = '';

        this._callback = function(hash) { };

    };



    $.extend(History.prototype, {



        init: function(callback) {

            this._callback = callback;

            this._curHash = location.hash;



            if ($.browser.msie) {

                // To stop the callback firing twice during initilization if no hash present

                if (this._curHash == '') {

                    this._curHash = '#';

                }



                // add hidden iframe for IE

                $("body").prepend('<iframe id="jQuery_history" style="display: none;"></iframe>');

                var iframe = $("#jQuery_history")[0].contentWindow.document;

                iframe.open();

                iframe.close();

                iframe.location.hash = this._curHash;

            }

            else if ($.browser.safari) {

                // etablish back/forward stacks

                this._historyBackStack = [];

                this._historyBackStack.length = history.length;

                this._historyForwardStack = [];

                this._isFirst = true;

                this._dontCheck = false;

            }

            this._callback(this._curHash.replace(/^#/, ''));

            setInterval(this._check, 100);

        },



        add: function(hash) {

            // This makes the looping function do something

            this._historyBackStack.push(hash);



            this._historyForwardStack.length = 0; // clear forwardStack (true click occured)

            this._isFirst = true;

        },



        _check: function() {

            if ($.browser.msie) {

                // On IE, check for location.hash of iframe

                var ihistory = $("#jQuery_history")[0];

                var iframe = ihistory.contentDocument || ihistory.contentWindow.document;

                var current_hash = iframe.location.hash;

                if (current_hash != $.history._curHash) {



                    location.hash = current_hash;

                    $.history._curHash = current_hash;

                    $.history._callback(current_hash.replace(/^#/, ''));



                }

            } else if ($.browser.safari) {

                if (!$.history._dontCheck) {

                    var historyDelta = history.length - $.history._historyBackStack.length;



                    if (historyDelta) { // back or forward button has been pushed

                        $.history._isFirst = false;

                        if (historyDelta < 0) { // back button has been pushed

                            // move items to forward stack

                            for (var i = 0; i < Math.abs(historyDelta); i++) $.history._historyForwardStack.unshift($.history._historyBackStack.pop());

                        } else { // forward button has been pushed

                            // move items to back stack

                            for (var i = 0; i < historyDelta; i++) $.history._historyBackStack.push($.history._historyForwardStack.shift());

                        }

                        var cachedHash = $.history._historyBackStack[$.history._historyBackStack.length - 1];

                        if (cachedHash != undefined) {

                            $.history._curHash = location.hash;

                            $.history._callback(cachedHash);

                        }

                    } else if ($.history._historyBackStack[$.history._historyBackStack.length - 1] == undefined && !$.history._isFirst) {

                        // back button has been pushed to beginning and URL already pointed to hash (e.g. a bookmark)

                        // document.URL doesn't change in Safari

                        if (document.URL.indexOf('#') >= 0) {

                            $.history._callback(document.URL.split('#')[1]);

                        } else {

                            $.history._callback('');

                        }

                        $.history._isFirst = true;

                    }

                }

            } else {

                // otherwise, check for location.hash

                var current_hash = location.hash;

                if (current_hash != $.history._curHash) {

                    $.history._curHash = current_hash;

                    $.history._callback(current_hash.replace(/^#/, ''));

                }

            }

        },



        load: function(hash) {

            var newhash;



            if ($.browser.safari) {

                newhash = hash;

            } else {

                newhash = '#' + hash;

                location.hash = newhash;

            }

            this._curHash = newhash;



            if ($.browser.msie) {

                var ihistory = $("#jQuery_history")[0]; // TODO: need contentDocument?

                var iframe = ihistory.contentWindow.document;

                iframe.open();

                iframe.close();

                iframe.location.hash = newhash;

                this._callback(hash);

            }

            else if ($.browser.safari) {

                this._dontCheck = true;

                // Manually keep track of the history values for Safari

                this.add(hash);



                // Wait a while before allowing checking so that Safari has time to update the "history" object

                // correctly (otherwise the check loop would detect a false change in hash).

                var fn = function() { $.history._dontCheck = false; };

                window.setTimeout(fn, 200);

                this._callback(hash);

                // N.B. "location.hash=" must be the last line of code for Safari as execution stops afterwards.

                //      By explicitly using the "location.hash" command (instead of using a variable set to "location.hash") the

                //      URL in the browser and the "history" object are both updated correctly.

                location.hash = newhash;

            }

            else {

                this._callback(hash);

            }

        }

    });



    $(document).ready(function() {

        $.history = new History(); // singleton instance

    });



})(jQuery);