/* Copyright (c) 2010, Yahoo! Inc. All rights reserved. Code licensed under the BSD License: http://developer.yahoo.com/yui/license.html version: 3.3.0 build: 3167 */ YUI.add('history-base', function(Y) { /** * Provides browser history management functionality using a simple * add/replace/get paradigm. This can be used to ensure that the browser's back * and forward buttons work as the user expects and to provide bookmarkable URLs * that return the user to the current application state, even in an Ajax * application that doesn't perform full-page refreshes. * * @module history * @since 3.2.0 */ /** * Provides global state management backed by an object, but with no browser * history integration. For actual browser history integration and back/forward * support, use the history-html5 or history-hash modules. * * @module history * @submodule history-base * @class HistoryBase * @uses EventTarget * @constructor * @param {Object} config (optional) configuration object, which may contain * zero or more of the following properties: * *
true
if value is a simple object and not a
* function or an array.
*
* @method _isSimpleObject
* @param {mixed} value
* @return {Boolean}
* @private
*/
function _isSimpleObject(value) {
return Lang.type(value) === 'object';
}
// -- Public Static Properties -------------------------------------------------
/**
* Name of this component.
*
* @property NAME
* @type String
* @static
*/
HistoryBase.NAME = 'historyBase';
/**
* Constant used to identify state changes originating from the
* add()
method.
*
* @property SRC_ADD
* @type String
* @static
* @final
*/
HistoryBase.SRC_ADD = SRC_ADD;
/**
* Constant used to identify state changes originating from the
* replace()
method.
*
* @property SRC_REPLACE
* @type String
* @static
* @final
*/
HistoryBase.SRC_REPLACE = SRC_REPLACE;
/**
* Whether or not this browser supports the HTML5 History API.
*
* @property html5
* @type Boolean
* @static
*/
// All HTML5-capable browsers except Gecko 2+ (Firefox 4+) correctly return
// true for 'onpopstate' in win. In order to support Gecko 2, we fall back to a
// UA sniff for now. (current as of Firefox 4.0b2)
HistoryBase.html5 = !!(win.history && win.history.pushState &&
win.history.replaceState && ('onpopstate' in win || Y.UA.gecko >= 2));
/**
* Whether or not this browser supports the window.onhashchange
* event natively. Note that even if this is true
, you may
* still want to use HistoryHash's synthetic hashchange
event
* since it normalizes implementation differences and fixes spec violations
* across various browsers.
*
* @property nativeHashChange
* @type Boolean
* @static
*/
// Most browsers that support hashchange expose it on the window. Opera 10.6+
// exposes it on the document (but you can still attach to it on the window).
//
// IE8 supports the hashchange event, but only in IE8 Standards
// Mode. However, IE8 in IE7 compatibility mode still defines the
// event but never fires it, so we can't just detect the event. We also can't
// just UA sniff for IE8, since other browsers support this event as well.
HistoryBase.nativeHashChange = ('onhashchange' in win || 'onhashchange' in doc) &&
(!docMode || docMode > 7);
Y.mix(HistoryBase.prototype, {
// -- Initialization -------------------------------------------------------
/**
* Initializes this HistoryBase instance. This method is called by the
* constructor.
*
* @method _init
* @param {Object} config configuration object
* @protected
*/
_init: function (config) {
var initialState;
/**
* Configuration object provided by the user on instantiation, or an
* empty object if one wasn't provided.
*
* @property _config
* @type Object
* @default {}
* @protected
*/
config = this._config = config || {};
/**
* Resolved initial state: a merge of the user-supplied initial state
* (if any) and any initial state provided by a subclass. This may
* differ from _config.initialState
. If neither the config
* nor a subclass supplies an initial state, this property will be
* null
.
*
* @property _initialState
* @type Object|null
* @default {}
* @protected
*/
initialState = this._initialState = this._initialState ||
config.initialState || null;
/**
* Fired when the state changes. To be notified of all state changes
* regardless of the History or YUI instance that generated them,
* subscribe to this event on Y.Global
. If you would rather
* be notified only about changes generated by this specific History
* instance, subscribe to this event on the instance.
*
* @event history:change
* @param {EventFacade} e Event facade with the following additional
* properties:
*
* newVal
and prevVal
properties
* representing the values of the item both before and after the
* change. If the item was newly added, prevVal
will be
* undefined
.
* null
or
* undefined
value will cause that key to be removed from the
* new state entry.
*
* @method add
* @param {Object} state Object hash of key/value pairs.
* @param {Object} options (optional) Zero or more of the following options:
*
* If true
(the default), the new state will be merged
* into the existing state. New values will override existing values,
* and null
or undefined
values will be
* removed from the state.
*
* If false
, the existing state will be discarded as a
* whole and the new state will take its place.
*
null
or undefined
value will cause the key to
* be removed from the new state entry.
*
* @method addValue
* @param {String} key State parameter key.
* @param {String} value New value.
* @param {Object} options (optional) Zero or more options. See
* add()
for a list of supported options.
* @chainable
*/
addValue: function (key, value, options) {
var state = {};
state[key] = value;
return this._change(SRC_ADD, state, options);
},
/**
* Returns the current value of the state parameter specified by key,
* or an object hash of key/value pairs for all current state parameters if
* no key is specified.
*
* @method get
* @param {String} key (optional) State parameter key.
* @return {Object|String} Value of the specified state parameter, or an
* object hash of key/value pairs for all current state parameters.
*/
get: function (key) {
var state = GlobalEnv._state,
isObject = _isSimpleObject(state);
if (key) {
return isObject && Obj.owns(state, key) ? state[key] : undefined;
} else {
return isObject ? Y.mix({}, state, true) : state; // mix provides a fast shallow clone.
}
},
/**
* Same as add()
except that a new browser history entry will
* not be created. Instead, the current history entry will be replaced with
* the new state.
*
* @method replace
* @param {Object} state Object hash of key/value pairs.
* @param {Object} options (optional) Zero or more options. See
* add()
for a list of supported options.
* @chainable
*/
replace: function () {
var args = YArray(arguments, 0, true);
args.unshift(SRC_REPLACE);
return this._change.apply(this, args);
},
/**
* Same as addValue()
except that a new browser history entry
* will not be created. Instead, the current history entry will be replaced
* with the new state.
*
* @method replaceValue
* @param {String} key State parameter key.
* @param {String} value New value.
* @param {Object} options (optional) Zero or more options. See
* add()
for a list of supported options.
* @chainable
*/
replaceValue: function (key, value, options) {
var state = {};
state[key] = value;
return this._change(SRC_REPLACE, state, options);
},
// -- Protected Methods ----------------------------------------------------
/**
* Changes the state. This method provides a common implementation shared by
* the public methods for changing state.
*
* @method _change
* @param {String} src Source of the change, for inclusion in event facades
* to facilitate filtering.
* @param {Object} state Object hash of key/value pairs.
* @param {Object} options (optional) Zero or more options. See
* add()
for a list of supported options.
* @protected
* @chainable
*/
_change: function (src, state, options) {
options = options ? Y.merge(DEFAULT_OPTIONS, options) : DEFAULT_OPTIONS;
if (options.merge && _isSimpleObject(state) &&
_isSimpleObject(GlobalEnv._state)) {
state = Y.merge(GlobalEnv._state, state);
}
this._resolveChanges(src, state, options);
return this;
},
/**
* Called by _resolveChanges() when the state has changed. This method takes
* care of actually firing the necessary events.
*
* @method _fireEvents
* @param {String} src Source of the changes, for inclusion in event facades
* to facilitate filtering.
* @param {Object} changes Resolved changes.
* @param {Object} options Zero or more options. See add()
for
* a list of supported options.
* @protected
*/
_fireEvents: function (src, changes, options) {
// Fire the global change event.
this.fire(EVT_CHANGE, {
_options: options,
changed : changes.changed,
newVal : changes.newState,
prevVal : changes.prevState,
removed : changes.removed,
src : src
});
// Fire change/remove events for individual items.
Obj.each(changes.changed, function (value, key) {
this._fireChangeEvent(src, key, value);
}, this);
Obj.each(changes.removed, function (value, key) {
this._fireRemoveEvent(src, key, value);
}, this);
},
/**
* Fires a dynamic "[key]Change" event.
*
* @method _fireChangeEvent
* @param {String} src source of the change, for inclusion in event facades
* to facilitate filtering
* @param {String} key key of the item that was changed
* @param {Object} value object hash containing newVal and
* prevVal properties for the changed item
* @protected
*/
_fireChangeEvent: function (src, key, value) {
/**
*
* Dynamic event fired when an individual history item is added or
* changed. The name of this event depends on the name of the key that
* changed. To listen to change events for a key named "foo", subscribe
* to the fooChange
event; for a key named "bar", subscribe
* to barChange
, etc.
*
* Key-specific events are only fired for instance-level changes; that
* is, changes that were made via the same History instance on which the
* event is subscribed. To be notified of changes made by other History
* instances, subscribe to the global history:change
event.
*
undefined
if the item was just added and has no
* previous value.
*
* Dynamic event fired when an individual history item is removed. The
* name of this event depends on the name of the key that was removed.
* To listen to remove events for a key named "foo", subscribe to the
* fooRemove
event; for a key named "bar", subscribe to
* barRemove
, etc.
*
* Key-specific events are only fired for instance-level changes; that
* is, changes that were made via the same History instance on which the
* event is subscribed. To be notified of changes made by other History
* instances, subscribe to the global history:change
event.
*
add()
for
* a list of supported options.
* @protected
*/
_resolveChanges: function (src, newState, options) {
var changed = {},
isChanged,
prevState = GlobalEnv._state,
removed = {};
if (!newState) {
newState = {};
}
if (!options) {
options = {};
}
if (_isSimpleObject(newState) && _isSimpleObject(prevState)) {
// Figure out what was added or changed.
Obj.each(newState, function (newVal, key) {
var prevVal = prevState[key];
if (newVal !== prevVal) {
changed[key] = {
newVal : newVal,
prevVal: prevVal
};
isChanged = true;
}
}, this);
// Figure out what was removed.
Obj.each(prevState, function (prevVal, key) {
if (!Obj.owns(newState, key) || newState[key] === null) {
delete newState[key];
removed[key] = prevVal;
isChanged = true;
}
}, this);
} else {
isChanged = newState !== prevState;
}
if (isChanged) {
this._fireEvents(src, {
changed : changed,
newState : newState,
prevState: prevState,
removed : removed
}, options);
}
},
/**
* Stores the specified state. Don't call this method directly; go through
* _resolveChanges() to ensure that changes are resolved and all events are
* fired properly.
*
* @method _storeState
* @param {String} src source of the changes
* @param {Object} newState new state to store
* @param {Object} options Zero or more options. See add()
for
* a list of supported options.
* @protected
*/
_storeState: function (src, newState) {
// Note: the src and options params aren't used here, but they are used
// by subclasses.
GlobalEnv._state = newState || {};
},
// -- Protected Event Handlers ---------------------------------------------
/**
* Default history:change
event handler.
*
* @method _defChangeFn
* @param {EventFacade} e state change event facade
* @protected
*/
_defChangeFn: function (e) {
this._storeState(e.src, e.newVal, e._options);
}
}, true);
Y.HistoryBase = HistoryBase;
}, '3.3.0' ,{requires:['event-custom-complex']});
YUI.add('history-hash', function(Y) {
/**
* Provides browser history management backed by
* window.location.hash
, as well as convenience methods for working
* with the location hash and a synthetic hashchange
event that
* normalizes differences across browsers.
*
* @module history
* @submodule history-hash
* @since 3.2.0
* @class HistoryHash
* @extends HistoryBase
* @constructor
* @param {Object} config (optional) Configuration object. See the HistoryBase
* documentation for details.
*/
var HistoryBase = Y.HistoryBase,
Lang = Y.Lang,
YArray = Y.Array,
YObject = Y.Object,
GlobalEnv = YUI.namespace('Env.HistoryHash'),
SRC_HASH = 'hash',
hashNotifiers,
oldHash,
oldUrl,
win = Y.config.win,
location = win.location,
useHistoryHTML5 = Y.config.useHistoryHTML5;
function HistoryHash() {
HistoryHash.superclass.constructor.apply(this, arguments);
}
Y.extend(HistoryHash, HistoryBase, {
// -- Initialization -------------------------------------------------------
_init: function (config) {
var bookmarkedState = HistoryHash.parseHash();
// If an initialState was provided, merge the bookmarked state into it
// (the bookmarked state wins).
config = config || {};
this._initialState = config.initialState ?
Y.merge(config.initialState, bookmarkedState) : bookmarkedState;
// Subscribe to the synthetic hashchange event (defined below) to handle
// changes.
Y.after('hashchange', Y.bind(this._afterHashChange, this), win);
HistoryHash.superclass._init.apply(this, arguments);
},
// -- Protected Methods ----------------------------------------------------
_change: function (src, state, options) {
// Stringify all values to ensure that comparisons don't fail after
// they're coerced to strings in the location hash.
YObject.each(state, function (value, key) {
if (Lang.isValue(value)) {
state[key] = value.toString();
}
});
return HistoryHash.superclass._change.call(this, src, state, options);
},
_storeState: function (src, newState) {
var decode = HistoryHash.decode,
newHash = HistoryHash.createHash(newState);
HistoryHash.superclass._storeState.apply(this, arguments);
// Update the location hash with the changes, but only if the new hash
// actually differs from the current hash (this avoids creating multiple
// history entries for a single state).
//
// We always compare decoded hashes, since it's possible that the hash
// could be set incorrectly to a non-encoded value outside of
// HistoryHash.
if (src !== SRC_HASH && decode(HistoryHash.getHash()) !== decode(newHash)) {
HistoryHash[src === HistoryBase.SRC_REPLACE ? 'replaceHash' : 'setHash'](newHash);
}
},
// -- Protected Event Handlers ---------------------------------------------
/**
* Handler for hashchange events.
*
* @method _afterHashChange
* @param {Event} e
* @protected
*/
_afterHashChange: function (e) {
this._resolveChanges(SRC_HASH, HistoryHash.parseHash(e.newHash), {});
}
}, {
// -- Public Static Properties ---------------------------------------------
NAME: 'historyHash',
/**
* Constant used to identify state changes originating from
* hashchange
events.
*
* @property SRC_HASH
* @type String
* @static
* @final
*/
SRC_HASH: SRC_HASH,
/**
*
* Prefix to prepend when setting the hash fragment. For example, if the
* prefix is !
and the hash fragment is set to
* #foo=bar&baz=quux
, the final hash fragment in the URL will
* become #!foo=bar&baz=quux
. This can be used to help make an
* Ajax application crawlable in accordance with Google's guidelines at
* http://code.google.com/web/ajaxcrawling/.
*
* Note that this prefix applies to all HistoryHash instances. It's not * possible for individual instances to use their own prefixes since they * all operate on the same URL. *
* * @property hashPrefix * @type String * @default '' * @static */ hashPrefix: '', // -- Protected Static Properties ------------------------------------------ /** * Regular expression used to parse location hash/query strings. * * @property _REGEX_HASH * @type RegExp * @protected * @static * @final */ _REGEX_HASH: /([^\?#&]+)=([^&]+)/g, // -- Public Static Methods ------------------------------------------------ /** * Creates a location hash string from the specified object of key/value * pairs. * * @method createHash * @param {Object} params object of key/value parameter pairs * @return {String} location hash string * @static */ createHash: function (params) { var encode = HistoryHash.encode, hash = []; YObject.each(params, function (value, key) { if (Lang.isValue(value)) { hash.push(encode(key) + '=' + encode(value)); } }); return hash.join('&'); }, /** * Wrapper arounddecodeURIComponent()
that also converts +
* chars into spaces.
*
* @method decode
* @param {String} string string to decode
* @return {String} decoded string
* @static
*/
decode: function (string) {
return decodeURIComponent(string.replace(/\+/g, ' '));
},
/**
* Wrapper around encodeURIComponent()
that converts spaces to
* + chars.
*
* @method encode
* @param {String} string string to encode
* @return {String} encoded string
* @static
*/
encode: function (string) {
return encodeURIComponent(string).replace(/%20/g, '+');
},
/**
* Gets the raw (not decoded) current location hash, minus the preceding '#'
* character and the hashPrefix (if one is set).
*
* @method getHash
* @return {String} current location hash
* @static
*/
getHash: (Y.UA.gecko ? function () {
// Gecko's window.location.hash returns a decoded string and we want all
// encoding untouched, so we need to get the hash value from
// window.location.href instead. We have to use UA sniffing rather than
// feature detection, since the only way to detect this would be to
// actually change the hash.
var matches = /#(.*)$/.exec(location.href),
hash = matches && matches[1] || '',
prefix = HistoryHash.hashPrefix;
return prefix && hash.indexOf(prefix) === 0 ?
hash.replace(prefix, '') : hash;
} : function () {
var hash = location.hash.substr(1),
prefix = HistoryHash.hashPrefix;
// Slight code duplication here, but execution speed is of the essence
// since getHash() is called every 50ms to poll for changes in browsers
// that don't support native onhashchange. An additional function call
// would add unnecessary overhead.
return prefix && hash.indexOf(prefix) === 0 ?
hash.replace(prefix, '') : hash;
}),
/**
* Gets the current bookmarkable URL.
*
* @method getUrl
* @return {String} current bookmarkable URL
* @static
*/
getUrl: function () {
return location.href;
},
/**
* Parses a location hash string into an object of key/value parameter
* pairs. If hash is not specified, the current location hash will
* be used.
*
* @method parseHash
* @param {String} hash (optional) location hash string
* @return {Object} object of parsed key/value parameter pairs
* @static
*/
parseHash: function (hash) {
var decode = HistoryHash.decode,
i,
len,
matches,
param,
params = {},
prefix = HistoryHash.hashPrefix,
prefixIndex;
hash = Lang.isValue(hash) ? hash : HistoryHash.getHash();
if (prefix) {
prefixIndex = hash.indexOf(prefix);
if (prefixIndex === 0 || (prefixIndex === 1 && hash.charAt(0) === '#')) {
hash = hash.replace(prefix, '');
}
}
matches = hash.match(HistoryHash._REGEX_HASH) || [];
for (i = 0, len = matches.length; i < len; ++i) {
param = matches[i].split('=');
params[decode(param[0])] = decode(param[1]);
}
return params;
},
/**
* Replaces the browser's current location hash with the specified hash
* and removes all forward navigation states, without creating a new browser
* history entry. Automatically prepends the hashPrefix
if one
* is set.
*
* @method replaceHash
* @param {String} hash new location hash
* @static
*/
replaceHash: function (hash) {
if (hash.charAt(0) === '#') {
hash = hash.substr(1);
}
location.replace('#' + (HistoryHash.hashPrefix || '') + hash);
},
/**
* Sets the browser's location hash to the specified string. Automatically
* prepends the hashPrefix
if one is set.
*
* @method setHash
* @param {String} hash new location hash
* @static
*/
setHash: function (hash) {
if (hash.charAt(0) === '#') {
hash = hash.substr(1);
}
location.hash = (HistoryHash.hashPrefix || '') + hash;
}
});
// -- Synthetic hashchange Event -----------------------------------------------
// TODO: YUIDoc currently doesn't provide a good way to document synthetic DOM
// events. For now, we're just documenting the hashchange event on the YUI
// object, which is about the best we can do until enhancements are made to
// YUIDoc.
/**
*
* Synthetic window.onhashchange
event that normalizes differences
* across browsers and provides support for browsers that don't natively support
* onhashchange
.
*
* This event is provided by the history-hash
module.
*
* Usage example: *
* *
* YUI().use('history-hash', function (Y) {
* Y.on('hashchange', function (e) {
* // Handle hashchange events on the current window.
* }, Y.config.win);
* });
*
*
* @event hashchange
* @param {EventFacade} e Event facade with the following additional
* properties:
*
* true
, the current
* history state will be replaced without adding a new history entry
* @protected
* @static
* @for HistoryHash
*/
HistoryHash._updateIframe = function (hash, replace) {
var iframeDoc = iframe && iframe.contentWindow && iframe.contentWindow.document,
iframeLocation = iframeDoc && iframeDoc.location;
if (!iframeDoc || !iframeLocation) {
return;
}
iframeDoc.open().close();
if (replace) {
iframeLocation.replace(hash.charAt(0) === '#' ? hash : '#' + hash);
} else {
iframeLocation.hash = hash;
}
};
Do.after(HistoryHash._updateIframe, HistoryHash, 'replaceHash', HistoryHash, true);
if (!iframe) {
Y.on('domready', function () {
// Create a hidden iframe to store history state, following the
// iframe-hiding recommendations from
// http://www.paciellogroup.com/blog/?p=604.
//
// This iframe will allow history navigation within the current page
// context. After navigating to another page, all but the most
// recent history state will be lost.
//
// Earlier versions of the YUI History Utility attempted to work
// around this limitation by having the iframe load a static
// resource. This workaround was extremely fragile and tended to
// break frequently (and silently) since it was entirely dependent
// on IE's inconsistent handling of iframe history.
//
// Since this workaround didn't work much of the time anyway and
// added significant complexity, it has been removed, and IE6 and 7
// now get slightly degraded history support.
iframe = GlobalEnv._iframe = Y.Node.getDOMNode(Y.Node.create(
''
));
// Append the iframe to the documentElement rather than the body.
// Keeping it outside the body prevents scrolling on the initial
// page load (hat tip to Ben Alman and jQuery BBQ for this
// technique).
Y.config.doc.documentElement.appendChild(iframe);
// Update the iframe with the initial location hash, if any. This
// will create an initial history entry that the user can return to
// after the state has changed.
HistoryHash._updateIframe(HistoryHash.getHash() || '#');
// Listen for hashchange events and keep the iframe's hash in sync
// with the parent frame's hash.
Y.on('hashchange', function (e) {
lastUrlHash = e.newHash;
if (HistoryHash.getIframeHash() !== lastUrlHash) {
HistoryHash._updateIframe(lastUrlHash);
}
}, win);
// Watch the iframe hash in order to detect back/forward navigation.
Y.later(50, null, function () {
var iframeHash = HistoryHash.getIframeHash();
if (iframeHash !== lastUrlHash) {
HistoryHash.setHash(iframeHash);
}
}, null, true);
});
}
}
}, '3.3.0' ,{requires:['history-hash', 'node-base']});
YUI.add('history-html5', function(Y) {
/**
* Provides browser history management using the HTML5 history API.
*
* @module history
* @submodule history-html5
* @since 3.2.0
*/
/**
* * Provides browser history management using the HTML5 history API. *
* *
* When calling the add()
, addValue()
,
* replace()
, or replaceValue()
methods on
* HistoryHTML5
, the following additional options are supported:
*
HistoryHTML5
-specific properties are supported in addition to
* those supported by HistoryBase
:
*
*
* Set this to true
to store the most recent history state in
* sessionStorage in order to seamlessly restore the previous state (if any)
* when HistoryHTML5
is instantiated after a
* window.onpopstate
event has already fired.
*
* By default, this setting is false
.
*
enableSessionFallback
config property is true
* and either Y.JSON
or native JSON support is available and
* session storage is supported.
*
* @method _storeSessionState
* @param {mixed} state State to store. May be any type serializable to
* JSON.
* @protected
*/
_storeSessionState: function (state) {
if (this._config[ENABLE_FALLBACK] && JSON && sessionStorage) {
sessionStorage[this._getSessionKey()] = JSON.stringify(state || null);
}
},
/**
* Overrides HistoryBase's _storeState()
and pushes or replaces
* a history entry using the HTML5 history API when necessary.
*
* @method _storeState
* @param {String} src Source of the changes.
* @param {Object} newState New state to store.
* @param {Object} options Zero or more options.
* @protected
*/
_storeState: function (src, newState, options) {
if (src !== SRC_POPSTATE) {
win.history[src === SRC_REPLACE ? 'replaceState' : 'pushState'](
newState, options.title || doc.title || '', options.url || null
);
}
this._storeSessionState(newState);
HistoryHTML5.superclass._storeState.apply(this, arguments);
},
// -- Protected Event Handlers ---------------------------------------------
/**
* Handler for popstate events.
*
* @method _onPopState
* @param {Event} e
* @protected
*/
_onPopState: function (e) {
var state = e._event.state;
this._storeSessionState(state);
this._resolveChanges(SRC_POPSTATE, state || null);
}
}, {
// -- Public Static Properties ---------------------------------------------
NAME: 'historyhtml5',
/**
* Constant used to identify state changes originating from
* popstate
events.
*
* @property SRC_POPSTATE
* @type String
* @static
* @final
*/
SRC_POPSTATE: SRC_POPSTATE
});
if (!Y.Node.DOM_EVENTS.popstate) {
Y.Node.DOM_EVENTS.popstate = 1;
}
Y.HistoryHTML5 = HistoryHTML5;
/**
*
* If true
, the Y.History
alias will always point to
* Y.HistoryHTML5
when the history-html5 module is loaded, even if
* the current browser doesn't support HTML5 history.
*
* If false
, the Y.History
alias will always point to
* Y.HistoryHash
when the history-hash module is loaded, even if
* the current browser supports HTML5 history.
*
* If neither true
nor false
, the
* Y.History
alias will point to the best available history adapter
* that the browser supports. This is the default behavior.
*