mirror of
https://github.com/moodle/moodle.git
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769 lines
26 KiB
JavaScript
Executable File
769 lines
26 KiB
JavaScript
Executable File
/*
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Copyright (c) 2007, Yahoo! Inc. All rights reserved.
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Code licensed under the BSD License:
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http://developer.yahoo.net/yui/license.txt
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version: 2.3.0
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*/
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/**
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* The Browser History Manager provides the ability to use the
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* back/forward navigation buttons in a DHTML application. It also allows
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* a DHTML application to be bookmarked in a specific state.
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*
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* @module history
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* @requires yahoo,event
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* @namespace YAHOO.util
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* @title Browser History Manager
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* @experimental
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*/
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/**
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* The History class provides the ability to use the back/forward navigation
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* buttons in a DHTML application. It also allows a DHTML application to
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* be bookmarked in a specific state.
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*
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* @class History
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* @constructor
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*/
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YAHOO.util.History = ( function () {
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/**
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* Our hidden IFrame used to store the browsing history.
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*
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* @property _iframe
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* @type HTMLIFrameElement
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* @default null
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* @private
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*/
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var _iframe = null;
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/**
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* INPUT field (with type="hidden" or type="text") or TEXTAREA.
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* This field keeps the value of the initial state, current state
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* the list of all states across pages within a single browser session.
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*
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* @property _storageField
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* @type HTMLInputElement|HTMLTextAreaElement
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* @default null
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* @private
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*/
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var _storageField = null;
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/**
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* Flag used to tell whether YAHOO.util.History.initialize has been called.
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*
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* @property _initialized
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* @type boolean
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* @default false
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* @private
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*/
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var _initialized = false;
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/**
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* Flag used to tell whether the storage field is ready to be used.
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*
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* @property _storageFieldReady
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* @type boolean
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* @default false
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* @private
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*/
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var _storageFieldReady = false;
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/**
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* Flag used to tell whether the Browser History Manager is ready.
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*
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* @property _bhmReady
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* @type boolean
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* @default false
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* @private
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*/
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var _bhmReady = false;
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/**
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* List of registered modules.
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*
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* @property _modules
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* @type array
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* @default []
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* @private
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*/
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var _modules = [];
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/**
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* List of fully qualified states. This is used only by Safari.
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*
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* @property _fqstates
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* @type array
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* @default []
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* @private
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*/
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var _fqstates = [];
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/**
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* Trims a string.
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*
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* @method _trim
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* @param {string} str The string to be trimmed.
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* @return {string} The trimmed string
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* @private
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*/
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function _trim( str ) {
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return str.replace( /^\s*(\S*(\s+\S+)*)\s*$/, "$1" );
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}
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/**
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* location.hash is a bit buggy on Opera. I have seen instances where
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* navigating the history using the back/forward buttons, and hence
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* changing the URL, would not change location.hash. That's ok, the
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* implementation of an equivalent is trivial.
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*
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* @method _getHash
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* @return {string} The hash portion of the document's location
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* @private
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*/
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function _getHash() {
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var href;
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var i;
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href = top.location.href;
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i = href.indexOf( "#" );
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return i >= 0 ? href.substr( i + 1 ) : null;
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}
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/**
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* Stores all the registered modules' initial state and current state.
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* On Safari, we also store all the fully qualified states visited by
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* the application within a single browser session. The storage takes
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* place in the form field specified during initialization.
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*
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* @method _storeStates
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* @private
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*/
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function _storeStates() {
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var moduleName;
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var moduleObj;
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var initialStates = [];
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var currentStates = [];
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for ( moduleName in _modules ) {
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if ( YAHOO.lang.hasOwnProperty( _modules, moduleName ) ) {
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moduleObj = _modules[moduleName];
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initialStates.push( moduleName + "=" + moduleObj.initialState );
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currentStates.push( moduleName + "=" + moduleObj.currentState );
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}
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}
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_storageField.value = initialStates.join( "&" ) + "|" + currentStates.join( "&" );
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if ( YAHOO.env.ua.webkit ) {
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_storageField.value += "|" + _fqstates.join( "," );
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}
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}
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/**
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* Sets the new currentState attribute of all modules depending on the new
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* fully qualified state. Also notifies the modules which current state has
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* changed.
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*
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* @method _handleFQStateChange
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* @param {string} fqstate Fully qualified state
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* @private
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*/
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function _handleFQStateChange( fqstate ) {
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var i;
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var len;
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var moduleName;
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var moduleObj;
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var modules;
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var states;
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var tokens;
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var currentState;
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if ( !fqstate ) {
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// Notifies all modules
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for ( moduleName in _modules ) {
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if ( YAHOO.lang.hasOwnProperty( _modules, moduleName ) ) {
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moduleObj = _modules[moduleName];
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moduleObj.currentState = moduleObj.initialState;
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moduleObj.onStateChange( unescape( moduleObj.currentState ) );
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}
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}
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return;
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}
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modules = [];
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states = fqstate.split( "&" );
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for ( i = 0, len = states.length ; i < len ; i++ ) {
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tokens = states[i].split( "=" );
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if ( tokens.length === 2 ) {
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moduleName = tokens[0];
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currentState = tokens[1];
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modules[moduleName] = currentState;
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}
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}
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for ( moduleName in _modules ) {
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if ( YAHOO.lang.hasOwnProperty( _modules, moduleName ) ) {
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moduleObj = _modules[moduleName];
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currentState = modules[moduleName];
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if ( !currentState || moduleObj.currentState !== currentState ) {
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moduleObj.currentState = currentState || moduleObj.initialState;
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moduleObj.onStateChange( unescape( moduleObj.currentState ) );
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}
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}
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}
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}
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/**
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* Periodically checks whether our internal IFrame is ready to be used.
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*
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* @method _checkIframeLoaded
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* @private
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*/
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function _checkIframeLoaded() {
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var doc;
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var elem;
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var fqstate;
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if ( !_iframe.contentWindow || !_iframe.contentWindow.document ) {
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// Check again in 10 msec...
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setTimeout( _checkIframeLoaded, 10 );
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return;
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}
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// Start the thread that will have the responsibility to
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// periodically check whether a navigate operation has been
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// requested on the main window. This will happen when
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// YAHOO.util.History.navigate has been called or after
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// the user has hit the back/forward button.
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doc = _iframe.contentWindow.document;
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elem = doc.getElementById( "state" );
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// We must use innerText, and not innerHTML because our string contains
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// the "&" character (which would end up being escaped as "&") and
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// the string comparison would fail...
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fqstate = elem ? elem.innerText : null;
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setInterval( function () {
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var newfqstate;
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var hash;
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var states;
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var moduleName;
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var moduleObj;
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doc = _iframe.contentWindow.document;
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elem = doc.getElementById( "state" );
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// See my comment above about using innerText instead of innerHTML...
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newfqstate = elem ? elem.innerText : null;
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if ( newfqstate !== fqstate ) {
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fqstate = newfqstate;
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_handleFQStateChange( fqstate );
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if ( !fqstate ) {
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states = [];
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for ( moduleName in _modules ) {
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if ( YAHOO.lang.hasOwnProperty( _modules, moduleName ) ) {
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moduleObj = _modules[moduleName];
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states.push( moduleName + "=" + moduleObj.initialState );
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}
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}
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hash = states.join( "&" );
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} else {
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hash = fqstate;
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}
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// Allow the state to be bookmarked by setting the top window's
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// URL fragment identifier. Note that here, we are on IE, and
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// IE does not touch the browser history when setting the hash
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// (unlike all the other browsers). I used to write:
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// top.location.replace( "#" + hash );
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// but this had a side effect when the page was not the top frame.
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top.location.hash = hash;
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_storeStates();
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}
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}, 50 );
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_bhmReady = true;
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YAHOO.util.History.onLoadEvent.fire();
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}
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/**
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* Finish up the initialization of the Browser History Manager.
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*
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* @method _initialize
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* @private
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*/
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function _initialize() {
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var i;
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var len;
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var parts;
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var tokens;
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var moduleName;
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var moduleObj;
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var initialStates;
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var initialState;
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var currentStates;
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var currentState;
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var counter;
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var hash;
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_storageField = document.getElementById( "yui_hist_field" );
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// Decode the content of our storage field...
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parts = _storageField.value.split( "|" );
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if ( parts.length > 1 ) {
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initialStates = parts[0].split( "&" );
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for ( i = 0, len = initialStates.length ; i < len ; i++ ) {
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tokens = initialStates[i].split( "=" );
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if ( tokens.length === 2 ) {
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moduleName = tokens[0];
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initialState = tokens[1];
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moduleObj = _modules[moduleName];
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if ( moduleObj ) {
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moduleObj.initialState = initialState;
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}
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}
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}
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currentStates = parts[1].split( "&" );
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for ( i = 0, len = currentStates.length ; i < len ; i++ ) {
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tokens = currentStates[i].split( "=" );
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if ( tokens.length >= 2 ) {
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moduleName = tokens[0];
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currentState = tokens[1];
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moduleObj = _modules[moduleName];
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if ( moduleObj ) {
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moduleObj.currentState = currentState;
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}
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}
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}
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}
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if ( parts.length > 2 ) {
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_fqstates = parts[2].split( "," );
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}
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_storageFieldReady = true;
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if ( YAHOO.env.ua.ie ) {
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_iframe = document.getElementById( "yui_hist_iframe" );
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_checkIframeLoaded();
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} else {
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// Start the thread that will have the responsibility to
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// periodically check whether a navigate operation has been
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// requested on the main window. This will happen when
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// YAHOO.util.History.navigate has been called or after
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// the user has hit the back/forward button.
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// On Safari 1.x and 2.0, the only way to catch a back/forward
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// operation is to watch history.length... We basically exploit
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// what I consider to be a bug (history.length is not supposed
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// to change when going back/forward in the history...) This is
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// why, in the following thread, we first compare the hash,
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// because the hash thing will be fixed in the next major
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// version of Safari. So even if they fix the history.length
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// bug, all this will still work!
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counter = history.length;
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// On Gecko and Opera, we just need to watch the hash...
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hash = _getHash();
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setInterval( function () {
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var state;
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var newHash;
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var newCounter;
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newHash = _getHash();
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newCounter = history.length;
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if ( newHash !== hash ) {
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hash = newHash;
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counter = newCounter;
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_handleFQStateChange( hash );
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_storeStates();
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} else if ( newCounter !== counter ) {
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// If we ever get here, we should be on Safari...
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hash = newHash;
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counter = newCounter;
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state = _fqstates[counter - 1];
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_handleFQStateChange( state );
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_storeStates();
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}
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}, 50 );
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_bhmReady = true;
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YAHOO.util.History.onLoadEvent.fire();
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}
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}
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return {
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/**
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* Fired when the Browser History Manager is ready.
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*
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* @event onLoadEvent
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*/
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onLoadEvent: new YAHOO.util.CustomEvent( "onLoad" ),
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/**
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* Registers a new module.
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*
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* @method register
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* @param {string} module Non-empty string uniquely identifying the
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* module you wish to register.
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* @param {string} initialState The initial state of the specified
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* module corresponding to its earliest history entry.
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* @param {function} onStateChange Callback called when the
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* state of the specified module has changed.
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* @param {object} obj An arbitrary object that will be passed as a
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* parameter to the handler.
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* @param {boolean} override If true, the obj passed in becomes the
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* execution scope of the listener.
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*/
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register: function ( module, initialState, onStateChange, obj, override ) {
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var scope;
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var wrappedFn;
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if ( typeof module !== "string" || _trim( module ) === "" ||
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typeof initialState !== "string" ||
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typeof onStateChange !== "function" ) {
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throw new Error( "Missing or invalid argument passed to YAHOO.util.History.register" );
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}
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if ( _modules[module] ) {
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// Here, we used to throw an exception. However, users have
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// complained about this behavior, so we now just return.
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return;
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}
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// Note: A module CANNOT be registered after calling
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// YAHOO.util.History.initialize. Indeed, we set the initial state
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// of each registered module in YAHOO.util.History.initialize.
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// If you could register a module after initializing the Browser
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// History Manager, you would not read the correct state using
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// YAHOO.util.History.getCurrentState when coming back to the
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// page using the back button.
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if ( _initialized ) {
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throw new Error( "All modules must be registered before calling YAHOO.util.History.initialize" );
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}
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// Make sure the strings passed in do not contain our separators "," and "|"
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module = escape( module );
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initialState = escape( initialState );
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// If the user chooses to override the scope, we use the
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// custom object passed in as the execution scope.
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scope = null;
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if ( override === true ) {
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scope = obj;
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} else {
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scope = override;
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}
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wrappedFn = function ( state ) {
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return onStateChange.call( scope, state, obj );
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};
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_modules[module] = {
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name: module,
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initialState: initialState,
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currentState: initialState,
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onStateChange: wrappedFn
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};
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},
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/**
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* Initializes the Browser History Manager. Call this method
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* from a script block located right after the opening body tag.
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*
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* @method initialize
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* @param {string} iframeTarget Optional - Path to an existing
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* HTML document accessible from the same domain. If not
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* specified, defaults to "blank.html". This is only useful
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* if you use https.
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* @public
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*/
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initialize: function ( iframeTarget ) {
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// Return if the browser history manager has already been initialized
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if ( _initialized ) {
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return;
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}
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if ( !iframeTarget ) {
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iframeTarget = "blank.html";
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}
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if ( typeof iframeTarget !== "string" || _trim( iframeTarget ) === "" ) {
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throw new Error( "Invalid argument passed to YAHOO.util.History.initialize" );
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}
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document.write( '<input type="hidden" id="yui_hist_field">' );
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if ( YAHOO.env.ua.ie ) {
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if ( location.protocol === "https:" ) {
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// If we use https, we MUST point the IFrame to a valid
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// document on the same server. If we don't, we will get
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// a warning (do you want to display non secure items?)
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document.write( '<iframe id="yui_hist_iframe" src="' + iframeTarget + '" style="position:absolute;visibility:hidden;"></iframe>' );
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} else {
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// This trick allows us to do without having to download
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// the asset, saving one HTTP request...
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document.write( '<iframe id="yui_hist_iframe" src="javascript:document.open();document.write("' + new Date().getTime() + '");document.close();" style="position:absolute;visibility:hidden;"></iframe>' );
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}
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}
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// We have to wait for the window's onload handler. Otherwise, our
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// hidden form field will always be empty (i.e. the browser won't
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// have had enough time to restore the session)
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YAHOO.util.Event.addListener( window, "load", _initialize );
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_initialized = true;
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},
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/**
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* Call this method when you want to store a new entry in the browser's history.
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*
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* @method navigate
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* @param {string} module Non-empty string representing your module.
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* @param {string} state String representing the new state of the specified module.
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* @return {boolean} Indicates whether the new state was successfully added to the history.
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* @public
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*/
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navigate: function ( module, state ) {
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var currentStates;
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var moduleName;
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var moduleObj;
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var currentState;
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var states;
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if ( typeof module !== "string" || typeof state !== "string" ) {
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throw new Error( "Missing or invalid argument passed to YAHOO.util.History.navigate" );
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}
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states = {};
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states[module] = state;
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return YAHOO.util.History.multiNavigate( states );
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},
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/**
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* Call this method when you want to store a new entry in the browser's history.
|
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*
|
|
* @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;
|
|
var moduleName;
|
|
var moduleObj;
|
|
var currentState;
|
|
var fqstate;
|
|
var html;
|
|
var doc;
|
|
|
|
if ( typeof states !== "object" ) {
|
|
throw new Error( "Missing or invalid argument passed to YAHOO.util.History.multiNavigate" );
|
|
}
|
|
|
|
if ( !_bhmReady ) {
|
|
throw new Error( "The Browser History Manager is not initialized" );
|
|
}
|
|
|
|
for ( moduleName in states ) {
|
|
if ( !_modules[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[moduleName];
|
|
} else {
|
|
currentState = moduleObj.currentState;
|
|
}
|
|
|
|
// Make sure the strings passed in do not contain our separators "," and "|"
|
|
moduleName = escape( moduleName );
|
|
currentState = escape( currentState );
|
|
|
|
currentStates.push( moduleName + "=" + currentState );
|
|
}
|
|
}
|
|
|
|
fqstate = currentStates.join( "&" );
|
|
|
|
if ( YAHOO.env.ua.ie ) {
|
|
|
|
html = '<html><body><div id="state">' + fqstate + '</div></body></html>';
|
|
try {
|
|
doc = _iframe.contentWindow.document;
|
|
doc.open();
|
|
doc.write( html );
|
|
doc.close();
|
|
} catch ( e ) {
|
|
return false;
|
|
}
|
|
|
|
} 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.
|
|
top.location.hash = fqstate;
|
|
if ( YAHOO.env.ua.webkit ) {
|
|
// The following two lines are only useful for Safari 1.x
|
|
// and 2.0. Recent nightly builds of WebKit do not require
|
|
// that, but unfortunately, it is not easy to differentiate
|
|
// between the two. Once Safari 2.0 departs the A-grade
|
|
// list, we can remove the following two lines...
|
|
_fqstates[history.length] = fqstate;
|
|
_storeStates();
|
|
}
|
|
|
|
}
|
|
|
|
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 passed to YAHOO.util.History.getCurrentState" );
|
|
}
|
|
|
|
if ( !_storageFieldReady ) {
|
|
throw new Error( "The Browser History Manager is not initialized" );
|
|
}
|
|
|
|
moduleObj = _modules[module];
|
|
if ( !moduleObj ) {
|
|
throw new Error( "No such registered module: " + module );
|
|
}
|
|
|
|
return unescape( 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;
|
|
var len;
|
|
var hash;
|
|
var states;
|
|
var tokens;
|
|
var moduleName;
|
|
|
|
if ( typeof module !== "string" ) {
|
|
throw new Error( "Missing or invalid argument passed to YAHOO.util.History.getBookmarkedState" );
|
|
}
|
|
|
|
hash = top.location.hash.substr(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 unescape( 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;
|
|
var len;
|
|
var idx;
|
|
var queryString;
|
|
var params;
|
|
var tokens;
|
|
|
|
url = url || top.location.href;
|
|
|
|
idx = url.indexOf( "?" );
|
|
queryString = idx >= 0 ? url.substr( idx + 1 ) : url;
|
|
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 unescape( tokens[1] );
|
|
}
|
|
}
|
|
}
|
|
|
|
return null;
|
|
}
|
|
|
|
};
|
|
|
|
} )();
|
|
YAHOO.register("history", YAHOO.util.History, {version: "2.3.0", build: "442"});
|