window.dhtmlHistory = {
initialize: function() { if (this.isInternetExplorer() == false) { return; } if (historyStorage.hasKey("DhtmlHistory_pageLoaded") == false) { this.fireOnNewListener = false; this.firstLoad = true; historyStorage.put("DhtmlHistory_pageLoaded", true); } else { this.fireOnNewListener = true; this.firstLoad = false;    } },
addListener: function(callback) { this.listener = callback; if (this.fireOnNewListener == true) { this.fireHistoryEvent(this.currentLocation); this.fireOnNewListener = false; } },
add: function(newLocation, historyData) { var self = this; var addImpl = function() { if (self.currentWaitTime > 0) { self.currentWaitTime = self.currentWaitTime - self.WAIT_TIME; } newLocation = self.removeHash(newLocation); var idCheck = document.getElementById(newLocation); if (idCheck != undefined || idCheck != null) { var message =  "Exception: History locations can not have " + "the same value as _any_ id's " + "that might be in the document, " + "due to a bug in Internet " + "Explorer; please ask the " + "developer to choose a history " + "location that does not match " + "any HTML id's in this " + "document. The following ID " + "is already taken and can not " + "be a location: "  + newLocation; throw message;  } historyStorage.put(newLocation, historyData); self.ignoreLocationChange = true; this.ieAtomicLocationChange = true; self.currentLocation = newLocation; window.location.hash = newLocation; if (self.isInternetExplorer()) { self.iframe.src = "blank.html?" + newLocation; } this.ieAtomicLocationChange = false; }; window.setTimeout(addImpl, this.currentWaitTime); this.currentWaitTime = this.currentWaitTime + this.WAIT_TIME; },
isFirstLoad: function() { if (this.firstLoad == true) { return true; } else { return false; } },
isInternational: function() { return false; },
getVersion: function() { return "0.05"; },
getCurrentLocation: function() { var currentLocation = this.removeHash(window.location.hash); return currentLocation; },
currentLocation: null,
listener: null,
iframe: null,
ignoreLocationChange: null,
WAIT_TIME: 400,
currentWaitTime: 0,
fireOnNewListener: null,
firstLoad: null,
ieAtomicLocationChange: null,          
create: function() { var initialHash = this.getCurrentLocation(); this.currentLocation = initialHash; if (this.isInternetExplorer()) { document.write("<iframe style='border: 0px; width: 1px; " + "height: 1px; position: absolute; bottom: 0px; " + "right: 0px; visibility: visible;' " + "name='DhtmlHistoryFrame' id='DhtmlHistoryFrame' " + "src='blank.html?" + initialHash + "'>" + "</iframe>"); this.WAIT_TIME = 400; } var self = this;
window.onunload = function() { self.firstLoad = null; }; if (this.isInternetExplorer() == false) { if (historyStorage.hasKey("DhtmlHistory_pageLoaded") == false) { this.ignoreLocationChange = true; this.firstLoad = true; historyStorage.put("DhtmlHistory_pageLoaded", true); } else { this.ignoreLocationChange = false; this.fireOnNewListener = true; } } else { this.ignoreLocationChange = true; } if (this.isInternetExplorer()) { this.iframe = document.getElementById("DhtmlHistoryFrame"); } var self = this; var locationHandler = function() { self.checkLocation(); }; setInterval(locationHandler, 100); },
fireHistoryEvent: function(newHash) { var historyData = historyStorage.get(newHash); this.listener.call(null, newHash, historyData); },
checkLocation: function() { if (this.isInternetExplorer() == false && this.ignoreLocationChange == true) { this.ignoreLocationChange = false; return; } if (this.isInternetExplorer() == false && this.ieAtomicLocationChange == true) { return; } var hash = this.getCurrentLocation(); if (hash == this.currentLocation) { return; } this.ieAtomicLocationChange = true; if (this.isInternetExplorer() && this.getIFrameHash() != hash) { this.iframe.src = "blank.html?" + hash; } else if (this.isInternetExplorer()) { return; } this.currentLocation = hash; this.ieAtomicLocationChange = false; this.fireHistoryEvent(hash); },  
getIFrameHash: function() { var historyFrame = document.getElementById("DhtmlHistoryFrame"); var doc = historyFrame.contentWindow.document; var hash = new String(doc.location.search); if (hash.length == 1 && hash.charAt(0) == "?") { hash = ""; } else if (hash.length >= 2 && hash.charAt(0) == "?") { hash = hash.substring(1);  } return hash; },          
removeHash: function(hashValue) { if (hashValue == null || hashValue == undefined) { return null; } else if (hashValue == "") { return ""; } else if (hashValue.length == 1 && hashValue.charAt(0) == "#") { return ""; } else if (hashValue.length > 1 && hashValue.charAt(0) == "#") { return hashValue.substring(1); } else { return hashValue; } },          
iframeLoaded: function(newLocation) { if (this.ignoreLocationChange == true) { this.ignoreLocationChange = false; return; } var hash = new String(newLocation.search); if (hash.length == 1 && hash.charAt(0) == "?") { hash = ""; } else if (hash.length >= 2 && hash.charAt(0) == "?") { hash = hash.substring(1); } if (this.pageLoadEvent != true) { window.location.hash = hash; } this.fireHistoryEvent(hash); },
isInternetExplorer: function() { var userAgent = navigator.userAgent.toLowerCase(); if (document.all && userAgent.indexOf('msie')!=-1) { return true; } else { return false; } }
};
window.historyStorage = {
debugging: false,
storageHash: new Object(),
hashLoaded: false,    
put: function(key, value) { this.assertValidKey(key); if (this.hasKey(key)) { this.remove(key); } this.storageHash[key] = value; this.saveHashTable();  },
get: function(key) { this.assertValidKey(key); this.loadHashTable(); var value = this.storageHash[key]; if (value == undefined) { return null; } else { return value;  } },
remove: function(key) { this.assertValidKey(key); this.loadHashTable(); delete this.storageHash[key]; this.saveHashTable(); },
reset: function() { this.storageField.value = ""; this.storageHash = new Object(); },
hasKey: function(key) { this.assertValidKey(key); this.loadHashTable(); if (typeof this.storageHash[key] == "undefined") { return false; } else { return true; } },
isValidKey: function(key) { return (typeof key == "string"); },
storageField: null,
init: function() { var styleValue = "position: absolute; top: -1000px; left: -1000px;"; if (this.debugging == true) { styleValue = "width: 30em; height: 30em;"; }   
var newContent = "<form id='historyStorageForm' "  + "method='GET' " + "style='" + styleValue + "'>" + "<textarea id='historyStorageField' " + "style='" + styleValue + "'" + "left: -1000px;' " + "name='historyStorageField'></textarea>" + "</form>"; document.write(newContent); this.storageField = document.getElementById("historyStorageField"); },
assertValidKey: function(key) { if (this.isValidKey(key) == false) { throw "Please provide a valid key for " + "window.historyStorage, key= " + key; } },
loadHashTable: function() { if (this.hashLoaded == false) { var serializedHashTable = this.storageField.value; if (serializedHashTable != "" && serializedHashTable != null) { this.storageHash = eval('(' + serializedHashTable + ')');   } this.hashLoaded = true; } },
saveHashTable: function() { this.loadHashTable(); var serializedHashTable = JSON.stringify(this.storageHash); this.storageField.value = serializedHashTable; }   
};
Array.prototype.______array = '______array';
var JSON = {
org: 'http://www.JSON.org',
copyright: '(c)2005 JSON.org',
license: 'http://www.crockford.com/JSON/license.html',
stringify: function (arg) { var c, i, l, s = '', v; switch (typeof arg) { case 'object': if (arg) { if (arg.______array == '______array') { for (i = 0; i < arg.length; ++i) { v = this.stringify(arg[i]); if (s) { s += ','; } s += v; } return '[' + s + ']'; } else if (typeof arg.toString != 'undefined') { for (i in arg) { v = arg[i]; if (typeof v != 'undefined' && typeof v != 'function') { v = this.stringify(v); if (s) { s += ','; } s += this.stringify(i) + ':' + v; } } return '{' + s + '}'; } } return 'null'; case 'number': return isFinite(arg) ? String(arg) : 'null'; case 'string': l = arg.length; s = '"'; for (i = 0; i < l; i += 1) { c = arg.charAt(i); if (c >= ' ') { if (c == '\\' || c == '"') { s += '\\'; } s += c; } else { switch (c) { case '\b': s += '\\b'; break; case '\f': s += '\\f'; break; case '\n': s += '\\n'; break; case '\r': s += '\\r'; break; case '\t': s += '\\t'; break; default: c = c.charCodeAt(); s += '\\u00' + Math.floor(c / 16).toString(16) + (c % 16).toString(16); } } } return s + '"'; case 'boolean': return String(arg); default: return 'null'; } },
parse: function (text) { var at = 0; var ch = ' '; function error(m) { throw { name: 'JSONError', message: m, at: at - 1, text: text }; }
function next() { ch = text.charAt(at); at += 1; return ch; }
function white() { while (ch != '' && ch <= ' ') { next(); } }
function str() { var i, s = '', t, u; if (ch == '"') { outer:          while (next()) { if (ch == '"') { next(); return s; } else if (ch == '\\') { switch (next()) { case 'b': s += '\b'; break; case 'f': s += '\f'; break; case 'n': s += '\n'; break; case 'r': s += '\r'; break; case 't': s += '\t'; break; case 'u': u = 0; for (i = 0; i < 4; i += 1) { t = parseInt(next(), 16); if (!isFinite(t)) { break outer; } u = u * 16 + t; } s += String.fromCharCode(u); break; default: s += ch; } } else { s += ch; } } } error("Bad string"); }
function arr() { var a = []; if (ch == '[') { next(); white(); if (ch == ']') { next(); return a; } while (ch) { a.push(val()); white(); if (ch == ']') { next(); return a; } else if (ch != ',') { break; } next(); white(); } } error("Bad array"); }
function obj() { var k, o = {}; if (ch == '{') { next(); white(); if (ch == '}') { next(); return o; } while (ch) { k = str(); white(); if (ch != ':') { break; } next(); o[k] = val(); white(); if (ch == '}') { next(); return o; } else if (ch != ',') { break; } next(); white(); } } error("Bad object"); }
function num() { var n = '', v; if (ch == '-') { n = '-'; next(); } while (ch >= '0' && ch <= '9') { n += ch; next(); } if (ch == '.') { n += '.'; while (next() && ch >= '0' && ch <= '9') { n += ch; } } if (ch == 'e' || ch == 'E') { n += 'e'; next(); if (ch == '-' || ch == '+') { n += ch; next(); } while (ch >= '0' && ch <= '9') { n += ch; next(); } } v = +n; if (!isFinite(v)) { error("Bad number"); } else { return v; } }
function word() { switch (ch) { case 't': if (next() == 'r' && next() == 'u' && next() == 'e') { next(); return true; } break; case 'f': if (next() == 'a' && next() == 'l' && next() == 's' && next() == 'e') { next(); return false; } break; case 'n': if (next() == 'u' && next() == 'l' && next() == 'l') { next(); return null; } break; } error("Syntax error"); }
function val() { white(); switch (ch) { case '{': return obj(); case '[': return arr(); case '"': return str(); case '-': return num(); default: return ch >= '0' && ch <= '9' ? num() : word(); } }
return val(); }
};
window.historyStorage.init();
window.dhtmlHistory.create();