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YUI.add('yui2-history', function(Y) {

    var YAHOO    = Y.YUI2;

    /*

Copyright (c) 2011, Yahoo! Inc. All rights reserved.

Code licensed under the BSD License:

http://developer.yahoo.com/yui/license.html

version: 2.9.0

*/

/**

 * The Browser History Manager provides the ability to use the back/forward

 * navigation buttons in a DHTML application. It also allows a DHTML

 * application to be bookmarked in a specific state.

 *

 * This library requires the following static markup:

 *

 * <iframe id="yui-history-iframe" src="path-to-real-asset-in-same-domain"></iframe>

 * <input id="yui-history-field" type="hidden">

 *

 * @module history

 * @requires yahoo,event

 * @namespace YAHOO.util

 * @title Browser History Manager

 */

/**

 * The History class provides the ability to use the back/forward navigation

 * buttons in a DHTML application. It also allows a DHTML application to

 * be bookmarked in a specific state.

 *

 * @class History

 * @constructor

 */

YAHOO.util.History = (function () {

    /**

     * Our hidden IFrame used to store the browsing history.

     *

     * @property _histFrame

     * @type HTMLIFrameElement

     * @default null

     * @private

     */

    var _histFrame = null;

    /**

     * INPUT field (with type="hidden" or type="text") or TEXTAREA.

     * This field keeps the value of the initial state, current state

     * the list of all states across pages within a single browser session.

     *

     * @property _stateField

     * @type HTMLInputElement|HTMLTextAreaElement

     * @default null

     * @private

     */

    var _stateField = null;

    /**

     * Flag used to tell whether YAHOO.util.History.initialize has been called.

     *

     * @property _initialized

     * @type boolean

     * @default false

     * @private

     */

    var _initialized = false;

    /**

     * List of registered modules.

     *

     * @property _modules

     * @type array

     * @default []

     * @private

     */

    var _modules = [];

    /**

     * List of fully qualified states. This is used only by Safari.

     *

     * @property _fqstates

     * @type array

     * @default []

     * @private

     */

    var _fqstates = [];

    /**

     * location.hash is a bit buggy on Opera. I have seen instances where

     * navigating the history using the back/forward buttons, and hence

     * changing the URL, would not change location.hash. That's ok, the

     * implementation of an equivalent is trivial.

     *

     * @method _getHash

     * @return {string} The hash portion of the document's location

     * @private

     */

    function _getHash() {

        var i, href;

        href = self.location.href;

        i = href.indexOf("#");

        return i >= 0 ? href.substr(i + 1) : null;

    }

    /**

     * Stores all the registered modules' initial state and current state.

     * On Safari, we also store all the fully qualified states visited by

     * the application within a single browser session. The storage takes

     * place in the form field specified during initialization.

     *

     * @method _storeStates

     * @private

     */

    function _storeStates() {

        var moduleName, moduleObj, initialStates = [], currentStates = [];

        for (moduleName in _modules) {

            if (YAHOO.lang.hasOwnProperty(_modules, moduleName)) {

                moduleObj = _modules[moduleName];

                initialStates.push(moduleName + "=" + moduleObj.initialState);

                currentStates.push(moduleName + "=" + moduleObj.currentState);

            }

        }

        _stateField.value = initialStates.join("&") + "|" + currentStates.join("&");

    }

    /**

     * Sets the new currentState attribute of all modules depending on the new

     * fully qualified state. Also notifies the modules which current state has

     * changed.

     *

     * @method _handleFQStateChange

     * @param {string} fqstate Fully qualified state

     * @private

     */

    function _handleFQStateChange(fqstate) {

        var i, len, moduleName, moduleObj, modules, states, tokens, currentState;

        if (!fqstate) {

            // Notifies all modules

            for (moduleName in _modules) {

                if (YAHOO.lang.hasOwnProperty(_modules, moduleName)) {

                    moduleObj = _modules[moduleName];

                    moduleObj.currentState = moduleObj.initialState;

                    moduleObj.onStateChange(_decode(moduleObj.currentState));

                }

            }

            return;

        }

        modules = [];

        states = fqstate.split("&");

        for (i = 0, len = states.length; i < len; i++) {

            tokens = states[i].split("=");

            if (tokens.length === 2) {

                moduleName = tokens[0];

                currentState = tokens[1];

                modules[moduleName] = currentState;

            }

        }

        for (moduleName in _modules) {

            if (YAHOO.lang.hasOwnProperty(_modules, moduleName)) {

                moduleObj = _modules[moduleName];

                currentState = modules[moduleName];

                if (!currentState || moduleObj.currentState !== currentState) {

                    moduleObj.currentState = typeof currentState === 'undefined' ? moduleObj.initialState : currentState;

                    moduleObj.onStateChange(_decode(moduleObj.currentState));

                }

            }

        }

    }

    /**

     * Update the IFrame with our new state.

     *

     * @method _updateIFrame

     * @private

     * @return {boolean} true if successful. false otherwise.

     */

    function _updateIFrame (fqstate) {

        var html, doc;

        html = '<html><body><div id="state">' +

                    YAHOO.lang.escapeHTML(fqstate) +

               '</div></body></html>';

        try {

            doc = _histFrame.contentWindow.document;

            doc.open();

            doc.write(html);

            doc.close();

            return true;

        } catch (e) {

            return false;

        }

    }

    /**

     * Periodically checks whether our internal IFrame is ready to be used.

     *

     * @method _checkIframeLoaded

     * @private

     */

    function _checkIframeLoaded() {

        var doc, elem, fqstate, hash;

        if (!_histFrame.contentWindow || !_histFrame.contentWindow.document) {

            // Check again in 10 msec...

            setTimeout(_checkIframeLoaded, 10);

            return;

        }

        // Start the thread that will have the responsibility to

        // periodically check whether a navigate operation has been

        // requested on the main window. This will happen when

        // YAHOO.util.History.navigate has been called or after

        // the user has hit the back/forward button.

        doc = _histFrame.contentWindow.document;

        elem = doc.getElementById("state");

        // We must use innerText, and not innerHTML because our string contains

        // the "&" character (which would end up being escaped as "&") and

        // the string comparison would fail...

        fqstate = elem ? elem.innerText : null;

        hash = _getHash();

        setInterval(function () {

            var newfqstate, states, moduleName, moduleObj, newHash, historyLength;

            doc = _histFrame.contentWindow.document;

            elem = doc.getElementById("state");

            // See my comment above about using innerText instead of innerHTML...

            newfqstate = elem ? elem.innerText : null;

            newHash = _getHash();

            if (newfqstate !== fqstate) {

                fqstate = newfqstate;

                _handleFQStateChange(fqstate);

                if (!fqstate) {

                    states = [];

                    for (moduleName in _modules) {

                        if (YAHOO.lang.hasOwnProperty(_modules, moduleName)) {

                            moduleObj = _modules[moduleName];

                            states.push(moduleName + "=" + moduleObj.initialState);

                        }

                    }

                    newHash = states.join("&");

                } else {

                    newHash = fqstate;

                }

                // Allow the state to be bookmarked by setting the top window's

                // URL fragment identifier. Note that here, we are on IE, and

                // IE does not touch the browser history when setting the hash

                // (unlike all the other browsers). I used to write:

                //     self.location.replace( "#" + hash );

                // but this had a side effect when the page was not the top frame.

                self.location.hash = newHash;

                hash = newHash;

                _storeStates();

            } else if (newHash !== hash) {

                // The hash has changed. The user might have clicked on a link,

                // or modified the URL directly, or opened the same application

                // bookmarked in a specific state using a bookmark. However, we

                // know the hash change was not caused by a hit on the back or

                // forward buttons, or by a call to navigate() (because it would

                // have been handled above) We must handle these cases, which is

                // why we also need to keep track of hash changes on IE!

                // Note that IE6 has some major issues with this kind of user

                // interaction (the history stack gets completely messed up)

                // but it seems to work fine on IE7.

                hash = newHash;

                // Now, store a new history entry. The following will cause the

                // code above to execute, doing all the dirty work for us...

                _updateIFrame(newHash);

            }

        }, 50);

        _initialized = true;

        YAHOO.util.History.onLoadEvent.fire();

    }

    /**

     * Finish up the initialization of the Browser History Manager.

     *

     * @method _initialize

     * @private

     */

    function _initialize() {

        var i, len, parts, tokens, moduleName, moduleObj, initialStates, initialState, currentStates, currentState, counter, hash;

        // Decode the content of our storage field...

        parts = _stateField.value.split("|");

        if (parts.length > 1) {

            initialStates = parts[0].split("&");

            for (i = 0, len = initialStates.length; i < len; i++) {

                tokens = initialStates[i].split("=");

                if (tokens.length === 2) {

                    moduleName = tokens[0];

                    initialState = tokens[1];

                    moduleObj = YAHOO.lang.hasOwnProperty(_modules, moduleName)

                            && _modules[moduleName];

                    if (moduleObj) {

                        moduleObj.initialState = initialState;

                    }

                }

            }

            currentStates = parts[1].split("&");

            for (i = 0, len = currentStates.length; i < len; i++) {

                tokens = currentStates[i].split("=");

                if (tokens.length >= 2) {

                    moduleName = tokens[0];

                    currentState = tokens[1];

                    moduleObj = YAHOO.lang.hasOwnProperty(_modules, moduleName)

                            && _modules[moduleName];

                    if (moduleObj) {

                        moduleObj.currentState = currentState;

                    }

                }

            }

        }

        if (parts.length > 2) {

            _fqstates = parts[2].split(",");

        }

        if (YAHOO.env.ua.ie) {

            if (typeof document.documentMode === "undefined" || document.documentMode < 8) {

                // IE < 8 or IE8 in quirks mode or IE7 standards mode

                _checkIframeLoaded();

            } else {

                // IE8 in IE8 standards mode

                YAHOO.util.Event.on(top, "hashchange",

                    function () {

                        var hash = _getHash();

                        _handleFQStateChange(hash);

                        _storeStates();

                    });

                _initialized = true;

                YAHOO.util.History.onLoadEvent.fire();

            }

        } else {

            // Start the thread that will have the responsibility to

            // periodically check whether a navigate operation has been

            // requested on the main window. This will happen when

            // YAHOO.util.History.navigate has been called or after

            // the user has hit the back/forward button.

            // On Gecko and Opera, we just need to watch the hash...

            hash = _getHash();

            setInterval(function () {

                var state, newHash, newCounter;

                newHash = _getHash();

                if (newHash !== hash) {

                    hash = newHash;

                    _handleFQStateChange(hash);

                    _storeStates();

                }

            }, 50);

            _initialized = true;

            YAHOO.util.History.onLoadEvent.fire();

        }

    }

    /**

     * Wrapper around <code>decodeURIComponent()</code> that also converts +

     * chars into spaces.

     *

     * @method _decode

     * @param {String} string string to decode

     * @return {String} decoded string

     * @private

     * @since 2.9.0

     */

    function _decode(string) {

        return decodeURIComponent(string.replace(/\+/g, ' '));

    }

    /**

     * Wrapper around <code>encodeURIComponent()</code> that converts spaces to

     * + chars.

     *

     * @method _encode

     * @param {String} string string to encode

     * @return {String} encoded string

     * @private

     * @since 2.9.0

     */

    function _encode(string) {

        return encodeURIComponent(string).replace(/%20/g, '+');

    }

    return {

        /**

         * Fired when the Browser History Manager is ready. If you subscribe to

         * this event after the Browser History Manager has been initialized,

         * it will not fire. Therefore, it is recommended to use the onReady

         * method instead.

         *

         * @event onLoadEvent

         * @see onReady

         */

        onLoadEvent: new YAHOO.util.CustomEvent("onLoad"),

        /**

         * Executes the supplied callback when the Browser History Manager is

         * ready. This will execute immediately if called after the Browser

         * History Manager onLoad event has fired.

         *

         * @method onReady

         * @param {function} fn what to execute when the Browser History Manager is ready.

         * @param {object} obj an optional object to be passed back as a parameter to fn.

         * @param {boolean|object} overrideContext If true, the obj passed in becomes fn's execution scope.

         * @see onLoadEvent

         */

        onReady: function (fn, obj, overrideContext) {

            if (_initialized) {

                setTimeout(function () {

                    var ctx = window;

                    if (overrideContext) {

                        if (overrideContext === true) {

                            ctx = obj;

                        } else {

                            ctx = overrideContext;

                        }

                    }

                    fn.call(ctx, "onLoad", [], obj);

                }, 0);

            } else {

                YAHOO.util.History.onLoadEvent.subscribe(fn, obj, overrideContext);

            }

        },

        /**

         * Registers a new module.

         *

         * @method register

         * @param {string} module Non-empty string uniquely identifying the

         *     module you wish to register.

         * @param {string} initialState The initial state of the specified

         *     module corresponding to its earliest history entry.

         * @param {function} onStateChange Callback called when the

         *     state of the specified module has changed.

         * @param {object} obj An arbitrary object that will be passed as a

         *     parameter to the handler.

         * @param {boolean} overrideContext If true, the obj passed in becomes the

         *     execution scope of the listener.

         */

        register: function (module, initialState, onStateChange, obj, overrideContext) {

            var scope, wrappedFn;

            if (typeof module !== "string" || YAHOO.lang.trim(module) === "" ||

                typeof initialState !== "string" ||

                typeof onStateChange !== "function") {

                throw new Error("Missing or invalid argument");

            }

            if (YAHOO.lang.hasOwnProperty(_modules, module)) {

                // Here, we used to throw an exception. However, users have

                // complained about this behavior, so we now just return.

                return;

            }

            // Note: A module CANNOT be registered after calling

            // YAHOO.util.History.initialize. Indeed, we set the initial state

            // of each registered module in YAHOO.util.History.initialize.

            // If you could register a module after initializing the Browser

            // History Manager, you would not read the correct state using

            // YAHOO.util.History.getCurrentState when coming back to the

            // page using the back button.

            if (_initialized) {

                throw new Error("All modules must be registered before calling YAHOO.util.History.initialize");

            }

            // Make sure the strings passed in do not contain our separators "," and "|"

            module = _encode(module);

            initialState = _encode(initialState);

            // If the user chooses to override the scope, we use the

            // custom object passed in as the execution scope.

            scope = null;

            if (overrideContext === true) {

                scope = obj;

            } else {

                scope = overrideContext;

            }

            wrappedFn = function (state) {

                return onStateChange.call(scope, state, obj);

            };

            _modules[module] = {

                name: module,

                initialState: initialState,

                currentState: initialState,

                onStateChange: wrappedFn

            };

        },

        /**

         * Initializes the Browser History Manager. Call this method

         * from a script block located right after the opening body tag.

         *

         * @method initialize

         * @param {string|HTML Element} stateField <input type="hidden"> used

         *     to store application states. Must be in the static markup.

         * @param {string|HTML Element} histFrame IFrame used to store

         *     the history (only required on Internet Explorer)

         * @public

         */

        initialize: function (stateField, histFrame) {

            if (_initialized) {

                // The browser history manager has already been initialized.

                return;

            }

            if (YAHOO.env.ua.opera && typeof history.navigationMode !== "undefined") {

                // Disable Opera's fast back/forward navigation mode and puts

                // it in compatible mode. This makes anchor-based history

                // navigation work after the page has been navigated away

                // from and re-activated, at the cost of slowing down

                // back/forward navigation to and from that page.

                history.navigationMode = "compatible";

            }

            if (typeof stateField === "string") {

                stateField = document.getElementById(stateField);

            }

            if (!stateField ||

                stateField.tagName.toUpperCase() !== "TEXTAREA" &&

                (stateField.tagName.toUpperCase() !== "INPUT" ||

                 stateField.type !== "hidden" &&

                 stateField.type !== "text")) {

                throw new Error("Missing or invalid argument");

            }

            _stateField = stateField;

            // IE < 8 or IE8 in quirks mode or IE7 standards mode

            if (YAHOO.env.ua.ie && (typeof document.documentMode === "undefined" || document.documentMode < 8)) {

                if (typeof histFrame === "string") {

                    histFrame = document.getElementById(histFrame);

                }

                if (!histFrame || histFrame.tagName.toUpperCase() !== "IFRAME") {

                    throw new Error("Missing or invalid argument");

                }

                _histFrame = histFrame;

            }

            // Note that the event utility MUST be included inline in the page.

            // If it gets loaded later (which you may want to do to improve the

            // loading speed of your site), the onDOMReady event never fires,

            // and the history library never gets fully initialized.

            YAHOO.util.Event.onDOMReady(_initialize);

        },

        /**

         * Call this method when you want to store a new entry in the browser's history.

         *

         * @method navigate

         * @param {string} module Non-empty string representing your module.

         * @param {string} state String representing the new state of the specified module.

         * @return {boolean} Indicates whether the new state was successfully added to the history.

         * @public

         */

        navigate: function (module, state) {

            var states;

            if (typeof module !== "string" || typeof state !== "string") {

                throw new Error("Missing or invalid argument");

            }

            states = {};

            states[module] = state;

            return YAHOO.util.History.multiNavigate(states);

        },

        /**

         * Call this method when you want to store a new entry in the browser's history.

         *

         * @method multiNavigate

         * @param {object} states Associative array of module-state pairs to set simultaneously.

         * @return {boolean} Indicates whether the new state was successfully added to the history.

         * @public

         */

        multiNavigate: function (states) {

            var currentStates, moduleName, moduleObj, currentState, fqstate;

            if (typeof states !== "object") {

                throw new Error("Missing or invalid argument");

            }

            if (!_initialized) {

                throw new Error("The Browser History Manager is not initialized");

            }

            for (moduleName in states) {

                if (!YAHOO.lang.hasOwnProperty(_modules, _encode(moduleName))) {

                    throw new Error("The following module has not been registered: " + moduleName);

                }

            }

            // Generate our new full state string mod1=xxx&mod2=yyy

            currentStates = [];

            for (moduleName in _modules) {

                if (YAHOO.lang.hasOwnProperty(_modules, moduleName)) {

                    moduleObj = _modules[moduleName];

                    if (YAHOO.lang.hasOwnProperty(states, moduleName)) {

                        currentState = states[_decode(moduleName)];

                    } else {

                        currentState = _decode(moduleObj.currentState);

                    }

                    // Make sure the strings passed in do not contain our separators "," and "|"

                    moduleName = _encode(moduleName);

                    currentState = _encode(currentState);

                    currentStates.push(moduleName + "=" + currentState);

                }

            }

            fqstate = currentStates.join("&");

            if (YAHOO.env.ua.ie && (typeof document.documentMode === "undefined" || document.documentMode < 8)) {

                return _updateIFrame(fqstate);

            } else {

                // Known bug: On Safari 1.x and 2.0, if you have tab browsing

                // enabled, Safari will show an endless loading icon in the

                // tab. This has apparently been fixed in recent WebKit builds.

                // One work around found by Dav Glass is to submit a form that

                // points to the same document. This indeed works on Safari 1.x

                // and 2.0 but creates bigger problems on WebKit. So for now,

                // we'll consider this an acceptable bug, and hope that Apple

                // comes out with their next version of Safari very soon.

                self.location.hash = fqstate;

                return true;

            }

        },

        /**

         * Returns the current state of the specified module.

         *

         * @method getCurrentState

         * @param {string} module Non-empty string representing your module.

         * @return {string} The current state of the specified module.

         * @public

         */

        getCurrentState: function (module) {

            var moduleObj;

            if (typeof module !== "string") {

                throw new Error("Missing or invalid argument");

            }

            if (!_initialized) {

                throw new Error("The Browser History Manager is not initialized");

            }

            moduleObj = YAHOO.lang.hasOwnProperty(_modules, module)

                    && _modules[module];

            if (!moduleObj) {

                throw new Error("No such registered module: " + module);

            }

            return _decode(moduleObj.currentState);

        },

        /**

         * Returns the state of a module according to the URL fragment

         * identifier. This method is useful to initialize your modules

         * if your application was bookmarked from a particular state.

         *

         * @method getBookmarkedState

         * @param {string} module Non-empty string representing your module.

         * @return {string} The bookmarked state of the specified module.

         * @public

         */

        getBookmarkedState: function (module) {

            var i, len, idx, hash, states, tokens, moduleName;

            if (typeof module !== "string") {

                throw new Error("Missing or invalid argument");

            }

            // Use location.href instead of location.hash which is already

            // URL-decoded, which creates problems if the state value

            // contained special characters...

            idx = self.location.href.indexOf("#");

            if (idx >= 0) {

                hash = self.location.href.substr(idx + 1);

                states = hash.split("&");

                for (i = 0, len = states.length; i < len; i++) {

                    tokens = states[i].split("=");

                    if (tokens.length === 2) {

                        moduleName = tokens[0];

                        if (moduleName === module) {

                            return _decode(tokens[1]);

                        }

                    }

                }

            }

            return null;

        },

        /**

         * Returns the value of the specified query string parameter.

         * This method is not used internally by the Browser History Manager.

         * However, it is provided here as a helper since many applications

         * using the Browser History Manager will want to read the value of

         * url parameters to initialize themselves.

         *

         * @method getQueryStringParameter

         * @param {string} paramName Name of the parameter we want to look up.

         * @param {string} queryString Optional URL to look at. If not specified,

         *     this method uses the URL in the address bar.

         * @return {string} The value of the specified parameter, or null.

         * @public

         */

        getQueryStringParameter: function (paramName, url) {

            var i, len, idx, queryString, params, tokens;

            url = url || self.location.href;

            idx = url.indexOf("?");

            queryString = idx >= 0 ? url.substr(idx + 1) : url;

            // Remove the hash if any

            idx = queryString.lastIndexOf("#");

            queryString = idx >= 0 ? queryString.substr(0, idx) : queryString;

            params = queryString.split("&");

            for (i = 0, len = params.length; i < len; i++) {

                tokens = params[i].split("=");

                if (tokens.length >= 2) {

                    if (tokens[0] === paramName) {

                        return _decode(tokens[1]);

                    }

                }

            }

            return null;

        }

    };

})();

YAHOO.register("history", YAHOO.util.History, {version: "2.9.0", build: "2800"});

}, '2.9.0' ,{"requires": ["yui2-yahoo", "yui2-event"]});