/adei/trunk

To get this branch, use:
bzr branch http://darksoft.org/webbzr/adei/trunk
1 by Suren A. Chilingaryan
Initial import
1
/*
2
Copyright (c) 2007 Brian Dillard and Brad Neuberg:
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Brian Dillard | Project Lead | bdillard@pathf.com | http://blogs.pathf.com/agileajax/
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Brad Neuberg | Original Project Creator | http://codinginparadise.org
5
   
6
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files
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(the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge,
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publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do
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so, subject to the following conditions:
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11
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
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FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
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WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*/
18
19
/*
20
	dhtmlHistory: An object that provides history, history data, and bookmarking for DHTML and Ajax applications.
21
	
22
	dependencies:
23
		* the historyStorage object included in this file.
24
25
*/
26
window.dhtmlHistory = {
27
	
28
	/*Public: User-agent booleans*/
29
	isIE: false,
30
	isOpera: false,
31
	isSafari: false,
32
	isKonquerer: false,
33
	isGecko: false,
34
	isSupported: false,
35
	
36
	/*Public: Create the DHTML history infrastructure*/
37
	create: function(options) {
38
		
39
		/*
40
			options - object to store initialization parameters
41
			options.debugMode - boolean that causes hidden form fields to be shown for development purposes.
42
			options.toJSON - function to override default JSON stringifier
43
			options.fromJSON - function to override default JSON parser
44
		*/
45
46
		var that = this;
47
48
		/*set user-agent flags*/
49
		var UA = navigator.userAgent.toLowerCase();
50
		var platform = navigator.platform.toLowerCase();
51
		var vendor = navigator.vendor || "";
52
		if (vendor === "KDE") {
53
			this.isKonqueror = true;
54
			this.isSupported = false;
55
		} else if (typeof window.opera !== "undefined") {
56
			this.isOpera = true;
57
			this.isSupported = true;
58
		} else if (typeof document.all !== "undefined") {
59
			this.isIE = true;
60
			this.isSupported = true;
61
		} else if (vendor.indexOf("Apple Computer, Inc.") > -1) {
62
			this.isSafari = true;
63
			this.isSupported = (platform.indexOf("mac") > -1);
64
		} else if (UA.indexOf("gecko") != -1) {
65
			this.isGecko = true;
66
			this.isSupported = true;
67
		}
68
69
		/*Set up the historyStorage object; pass in init parameters*/
70
		window.historyStorage.setup(options);
71
72
		/*Execute browser-specific setup methods*/
73
		if (this.isSafari) {
74
			this.createSafari();
75
		} else if (this.isOpera) {
76
			this.createOpera();
77
		}
78
		
79
		/*Get our initial location*/
80
		var initialHash = this.getCurrentLocation();
81
82
		/*Save it as our current location*/
83
		this.currentLocation = initialHash;
84
85
		/*Now that we have a hash, create IE-specific code*/
86
		if (this.isIE) {
87
			this.createIE(initialHash);
88
		}
89
90
		/*Add an unload listener for the page; this is needed for FF 1.5+ because this browser caches all dynamic updates to the
91
		page, which can break some of our logic related to testing whether this is the first instance a page has loaded or whether
92
		it is being pulled from the cache*/
93
94
		var unloadHandler = function() {
95
			that.firstLoad = null;
96
		};
97
		
98
		this.addEventListener(window,'unload',unloadHandler);		
99
100
		/*Determine if this is our first page load; for IE, we do this in this.iframeLoaded(), which is fired on pageload. We do it
101
		there because we have no historyStorage at this point, which only exists after the page is finished loading in IE*/
102
		if (this.isIE) {
103
			/*The iframe will get loaded on page load, and we want to ignore this fact*/
104
			this.ignoreLocationChange = true;
105
		} else {
106
			if (!historyStorage.hasKey(this.PAGELOADEDSTRING)) {
107
				/*This is our first page load, so ignore the location change and add our special history entry*/
108
				this.ignoreLocationChange = true;
109
				this.firstLoad = true;
110
				historyStorage.put(this.PAGELOADEDSTRING, true);
111
			} else {
112
				/*This isn't our first page load, so indicate that we want to pay attention to this location change*/
113
				this.ignoreLocationChange = false;
114
				/*For browsers other than IE, fire a history change event; on IE, the event will be thrown automatically when its
115
				hidden iframe reloads on page load. Unfortunately, we don't have any listeners yet; indicate that we want to fire
116
				an event when a listener is added.*/
117
				this.fireOnNewListener = true;
118
			}
119
		}
120
121
		/*Other browsers can use a location handler that checks at regular intervals as their primary mechanism; we use it for IE as
122
		well to handle an important edge case; see checkLocation() for details*/
123
		var locationHandler = function() {
124
			that.checkLocation();
125
		};
126
		setInterval(locationHandler, 100);
127
	},	
128
	
129
	/*Public: Initialize our DHTML history. You must call this after the page is finished loading.*/
130
	initialize: function() {
131
		/*IE needs to be explicitly initialized. IE doesn't autofill form data until the page is finished loading, so we have to wait*/
132
		if (this.isIE) {
133
			/*If this is the first time this page has loaded*/
134
			if (!historyStorage.hasKey(this.PAGELOADEDSTRING)) {
135
				/*For IE, we do this in initialize(); for other browsers, we do it in create()*/
136
				this.fireOnNewListener = false;
137
				this.firstLoad = true;
138
				historyStorage.put(this.PAGELOADEDSTRING, true);
139
			}
140
			/*Else if this is a fake onload event*/
141
			else {
142
				this.fireOnNewListener = true;
143
				this.firstLoad = false;   
144
			}
145
		}
146
	},
147
148
	/*Public: Adds a history change listener. Note that only one listener is supported at this time.*/
149
	addListener: function(listener) {
150
		this.listener = listener;
151
		/*If the page was just loaded and we should not ignore it, fire an event to our new listener now*/
152
		if (this.fireOnNewListener) {
153
			this.fireHistoryEvent(this.currentLocation);
154
			this.fireOnNewListener = false;
155
		}
156
	},
157
	
158
	/*Public: Generic utility function for attaching events*/
159
	addEventListener: function(o,e,l) {
160
		if (o.addEventListener) {
161
			o.addEventListener(e,l,false);
162
		} else if (o.attachEvent) {
163
			o.attachEvent('on'+e,function() {
164
				l(window.event);
165
			});
166
		}
167
	},
168
	
169
	/*Public: Add a history point.*/
170
	add: function(newLocation, historyData) {
171
		
172
		if (this.isSafari) {
173
			
174
			/*Remove any leading hash symbols on newLocation*/
175
			newLocation = this.removeHash(newLocation);
176
177
			/*Store the history data into history storage*/
178
			historyStorage.put(newLocation, historyData);
179
180
			/*Save this as our current location*/
181
			this.currentLocation = newLocation;
182
	
183
			/*Change the browser location*/
184
			window.location.hash = newLocation;
185
		
186
			/*Save this to the Safari form field*/
187
			this.putSafariState(newLocation);
188
189
		} else {
190
			
191
			/*Most browsers require that we wait a certain amount of time before changing the location, such
192
			as 200 MS; rather than forcing external callers to use window.setTimeout to account for this,
193
			we internally handle it by putting requests in a queue.*/
194
			var that = this;
195
			var addImpl = function() {
196
197
				/*Indicate that the current wait time is now less*/
198
				if (that.currentWaitTime > 0) {
199
					that.currentWaitTime = that.currentWaitTime - that.waitTime;
200
				}
201
			
202
				/*Remove any leading hash symbols on newLocation*/
203
				newLocation = that.removeHash(newLocation);
204
205
				/*IE has a strange bug; if the newLocation is the same as _any_ preexisting id in the
206
				document, then the history action gets recorded twice; throw a programmer exception if
207
				there is an element with this ID*/
208
				if (document.getElementById(newLocation) && that.debugMode) {
209
					var e = "Exception: History locations can not have the same value as _any_ IDs that might be in the document,"
210
					+ " due to a bug in IE; please ask the developer to choose a history location that does not match any HTML"
211
					+ " IDs in this document. The following ID is already taken and cannot be a location: " + newLocation;
212
					throw new Error(e); 
213
				}
214
215
				/*Store the history data into history storage*/
216
				historyStorage.put(newLocation, historyData);
217
218
				/*Indicate to the browser to ignore this upcomming location change since we're making it programmatically*/
219
				that.ignoreLocationChange = true;
220
221
				/*Indicate to IE that this is an atomic location change block*/
222
				that.ieAtomicLocationChange = true;
223
224
				/*Save this as our current location*/
225
				that.currentLocation = newLocation;
226
		
227
				/*Change the browser location*/
228
				window.location.hash = newLocation;
229
230
				/*Change the hidden iframe's location if on IE*/
231
				if (that.isIE) {
232
					that.iframe.src = "blank.html?" + newLocation;
233
				}
234
235
				/*End of atomic location change block for IE*/
236
				that.ieAtomicLocationChange = false;
237
			};
238
239
			/*Now queue up this add request*/
240
			window.setTimeout(addImpl, this.currentWaitTime);
241
242
			/*Indicate that the next request will have to wait for awhile*/
243
			this.currentWaitTime = this.currentWaitTime + this.waitTime;
244
		}
245
	},
246
247
	/*Public*/
248
	isFirstLoad: function() {
249
		return this.firstLoad;
250
	},
251
252
	/*Public*/
253
	getVersion: function() {
254
		return "0.6";
255
	},
256
257
	/*Get browser's current hash location; for Safari, read value from a hidden form field*/
258
259
	/*Public*/
260
	getCurrentLocation: function() {
261
		var r = (this.isSafari
262
			? this.getSafariState()
263
			: this.getCurrentHash()
264
		);
265
		return r;
266
	},
267
	
268
	/*Public: Manually parse the current url for a hash; tip of the hat to YUI*/
269
    getCurrentHash: function() {
270
		var r = window.location.href;
271
		var i = r.indexOf("#");
272
		return (i >= 0
273
			? r.substr(i+1)
274
			: ""
275
		);
276
    },
277
	
278
	/*- - - - - - - - - - - -*/
279
	
280
	/*Private: Constant for our own internal history event called when the page is loaded*/
281
	PAGELOADEDSTRING: "DhtmlHistory_pageLoaded",
282
	
283
	/*Private: Our history change listener.*/
284
	listener: null,
285
286
	/*Private: MS to wait between add requests - will be reset for certain browsers*/
287
	waitTime: 200,
288
	
289
	/*Private: MS before an add request can execute*/
290
	currentWaitTime: 0,
291
292
	/*Private: Our current hash location, without the "#" symbol.*/
293
	currentLocation: null,
294
295
	/*Private: Hidden iframe used to IE to detect history changes*/
296
	iframe: null,
297
298
	/*Private: Flags and DOM references used only by Safari*/
299
	safariHistoryStartPoint: null,
300
	safariStack: null,
301
	safariLength: null,
302
303
	/*Private: Flag used to keep checkLocation() from doing anything when it discovers location changes we've made ourselves
304
	programmatically with the add() method. Basically, add() sets this to true. When checkLocation() discovers it's true,
305
	it refrains from firing our listener, then resets the flag to false for next cycle. That way, our listener only gets fired on
306
	history change events triggered by the user via back/forward buttons and manual hash changes. This flag also helps us set up
307
	IE's special iframe-based method of handling history changes.*/
308
	ignoreLocationChange: null,
309
310
	/*Private: A flag that indicates that we should fire a history change event when we are ready, i.e. after we are initialized and
311
	we have a history change listener. This is needed due to an edge case in browsers other than IE; if you leave a page entirely
312
	then return, we must fire this as a history change event. Unfortunately, we have lost all references to listeners from earlier,
313
	because JavaScript clears out.*/
314
	fireOnNewListener: null,
315
316
	/*Private: A variable that indicates whether this is the first time this page has been loaded. If you go to a web page, leave it
317
	for another one, and then return, the page's onload listener fires again. We need a way to differentiate between the first page
318
	load and subsequent ones. This variable works hand in hand with the pageLoaded variable we store into historyStorage.*/
319
	firstLoad: null,
320
321
	/*Private: A variable to handle an important edge case in IE. In IE, if a user manually types an address into their browser's
322
	location bar, we must intercept this by calling checkLocation() at regular intervals. However, if we are programmatically
323
	changing the location bar ourselves using the add() method, we need to ignore these changes in checkLocation(). Unfortunately,
324
	these changes take several lines of code to complete, so for the duration of those lines of code, we set this variable to true.
325
	That signals to checkLocation() to ignore the change-in-progress. Once we're done with our chunk of location-change code in
326
	add(), we set this back to false. We'll do the same thing when capturing user-entered address changes in checkLocation itself.*/
327
	ieAtomicLocationChange: null,
328
	
329
	/*Private: Create IE-specific DOM nodes and overrides*/
330
	createIE: function(initialHash) {
331
		/*write out a hidden iframe for IE and set the amount of time to wait between add() requests*/
332
		this.waitTime = 400;/*IE needs longer between history updates*/
333
		var styles = (historyStorage.debugMode
334
			? 'width: 800px;height:80px;border:1px solid black;'
335
			: historyStorage.hideStyles
336
		);
337
		var iframeID = "rshHistoryFrame";
338
		var iframeHTML = '<iframe frameborder="0" id="' + iframeID + '" style="' + styles + '" src="blank.html?' + initialHash + '"></iframe>';
339
		document.write(iframeHTML);
340
		this.iframe = document.getElementById(iframeID);
341
	},
342
	
343
	/*Private: Create Opera-specific DOM nodes and overrides*/
344
	createOpera: function() {
345
		this.waitTime = 400;/*Opera needs longer between history updates*/
346
		var imgHTML = '<img src="javascript:location.href=\'javascript:dhtmlHistory.checkLocation();\';" style="' + historyStorage.hideStyles + '" />';
347
		document.write(imgHTML);
348
	},
349
	
350
	/*Private: Create Safari-specific DOM nodes and overrides*/
351
	createSafari: function() {
352
		var formID = "rshSafariForm";
353
		var stackID = "rshSafariStack";
354
		var lengthID = "rshSafariLength";
355
		var formStyles = historyStorage.debugMode ? historyStorage.showStyles : historyStorage.hideStyles;
356
		var inputStyles = (historyStorage.debugMode
357
			? 'width:800px;height:20px;border:1px solid black;margin:0;padding:0;'
358
			: historyStorage.hideStyles
359
		);
360
		var safariHTML = '<form id="' + formID + '" style="' + formStyles + '">'
361
			+ '<input type="text" style="' + inputStyles + '" id="' + stackID + '" value="[]"/>'
362
			+ '<input type="text" style="' + inputStyles + '" id="' + lengthID + '" value=""/>'
363
		+ '</form>';
364
		document.write(safariHTML);
365
		this.safariStack = document.getElementById(stackID);
366
		this.safariLength = document.getElementById(lengthID);
367
		if (!historyStorage.hasKey(this.PAGELOADEDSTRING)) {
368
			this.safariHistoryStartPoint = history.length;
369
			this.safariLength.value = this.safariHistoryStartPoint;
370
		} else {
371
			this.safariHistoryStartPoint = this.safariLength.value;
372
		}
373
	},
374
	
375
	/*Private: Safari method to read the history stack from a hidden form field*/
376
	getSafariStack: function() {
377
		var r = this.safariStack.value;
378
		return historyStorage.fromJSON(r);
379
	},
380
381
	/*Private: Safari method to read from the history stack*/
382
	getSafariState: function() {
383
		var stack = this.getSafariStack();
384
		var state = stack[history.length - this.safariHistoryStartPoint - 1];
385
		return state;
386
	},			
387
	/*Private: Safari method to write the history stack to a hidden form field*/
388
	putSafariState: function(newLocation) {
389
	    var stack = this.getSafariStack();
390
	    stack[history.length - this.safariHistoryStartPoint] = newLocation;
391
	    this.safariStack.value = historyStorage.toJSON(stack);
392
	},
393
394
	/*Private: Notify the listener of new history changes.*/
395
	fireHistoryEvent: function(newHash) {
396
		/*extract the value from our history storage for this hash*/
397
		var historyData = historyStorage.get(newHash);
398
		/*call our listener*/
399
		this.listener.call(null, newHash, historyData);
400
	},
401
	
402
	/*Private: See if the browser has changed location. This is the primary history mechanism for Firefox. For IE, we use this to
403
	handle an important edge case: if a user manually types in a new hash value into their IE location bar and press enter, we want to
404
	to intercept this and notify any history listener.*/
405
	checkLocation: function() {
406
		
407
		/*Ignore any location changes that we made ourselves for browsers other than IE*/
408
		if (!this.isIE && this.ignoreLocationChange) {
409
			this.ignoreLocationChange = false;
410
			return;
411
		}
412
413
		/*If we are dealing with IE and we are in the middle of making a location change from an iframe, ignore it*/
414
		if (!this.isIE && this.ieAtomicLocationChange) {
415
			return;
416
		}
417
		
418
		/*Get hash location*/
419
		var hash = this.getCurrentLocation();
420
421
		/*Do nothing if there's been no change*/
422
		if (hash == this.currentLocation) {
423
			return;
424
		}
425
426
		/*In IE, users manually entering locations into the browser; we do this by comparing the browser's location against the
427
		iframe's location; if they differ, we are dealing with a manual event and need to place it inside our history, otherwise
428
		we can return*/
429
		this.ieAtomicLocationChange = true;
430
431
		if (this.isIE && this.getIframeHash() != hash) {
432
			this.iframe.src = "blank.html?" + hash;
433
		}
434
		else if (this.isIE) {
435
			/*the iframe is unchanged*/
436
			return;
437
		}
438
439
		/*Save this new location*/
440
		this.currentLocation = hash;
441
442
		this.ieAtomicLocationChange = false;
443
444
		/*Notify listeners of the change*/
445
		this.fireHistoryEvent(hash);
446
	},
447
448
	/*Private: Get the current location of IE's hidden iframe.*/
449
	getIframeHash: function() {
450
		var doc = this.iframe.contentWindow.document;
451
		var hash = String(doc.location.search);
452
		if (hash.length == 1 && hash.charAt(0) == "?") {
453
			hash = "";
454
		}
455
		else if (hash.length >= 2 && hash.charAt(0) == "?") {
456
			hash = hash.substring(1);
457
		}
458
		return hash;
459
	},
460
461
	/*Private: Remove any leading hash that might be on a location.*/
462
	removeHash: function(hashValue) {
463
		var r;
464
		if (hashValue === null || hashValue === undefined) {
465
			r = null;
466
		}
467
		else if (hashValue === "") {
468
			r = "";
469
		}
470
		else if (hashValue.length == 1 && hashValue.charAt(0) == "#") {
471
			r = "";
472
		}
473
		else if (hashValue.length > 1 && hashValue.charAt(0) == "#") {
474
			r = hashValue.substring(1);
475
		}
476
		else {
477
			r = hashValue;
478
		}
479
		return r;
480
	},
481
482
	/*Private: For IE, tell when the hidden iframe has finished loading.*/
483
	iframeLoaded: function(newLocation) {
484
		/*ignore any location changes that we made ourselves*/
485
		if (this.ignoreLocationChange) {
486
			this.ignoreLocationChange = false;
487
			return;
488
		}
489
490
		/*Get the new location*/
491
		var hash = String(newLocation.search);
492
		if (hash.length == 1 && hash.charAt(0) == "?") {
493
			hash = "";
494
		}
495
		else if (hash.length >= 2 && hash.charAt(0) == "?") {
496
			hash = hash.substring(1);
497
		}
498
		/*Keep the browser location bar in sync with the iframe hash*/
499
		window.location.hash = hash;
500
501
		/*Notify listeners of the change*/
502
		this.fireHistoryEvent(hash);
503
	}
504
505
};
506
507
/*
508
	historyStorage: An object that uses a hidden form to store history state across page loads. The mechanism for doing so relies on
509
	the fact that browsers save the text in form data for the life of the browser session, which means the text is still there when
510
	the user navigates back to the page. This object can be used independently of the dhtmlHistory object for caching of Ajax
511
	session information.
512
	
513
	dependencies: 
514
		* json2007.js (included in a separate file) or alternate JSON methods passed in through an options bundle.
515
*/
516
window.historyStorage = {
517
	
518
	/*Public: Set up our historyStorage object for use by dhtmlHistory or other objects*/
519
	setup: function(options) {
520
		
521
		/*
522
			options - object to store initialization parameters - passed in from dhtmlHistory or directly into historyStorage
523
			options.debugMode - boolean that causes hidden form fields to be shown for development purposes.
524
			options.toJSON - function to override default JSON stringifier
525
			options.fromJSON - function to override default JSON parser
526
		*/
527
		
528
		/*process init parameters*/
529
		if (typeof options !== "undefined") {
530
			if (options.debugMode) {
531
				this.debugMode = options.debugMode;
532
			}
533
			if (options.toJSON) {
534
				this.toJSON = options.toJSON;
535
			}
536
			if (options.fromJSON) {
537
				this.fromJSON = options.fromJSON;
538
			}
539
		}		
540
		
541
		/*write a hidden form and textarea into the page; we'll stow our history stack here*/
542
		var formID = "rshStorageForm";
543
		var textareaID = "rshStorageField";
544
		var formStyles = this.debugMode ? historyStorage.showStyles : historyStorage.hideStyles;
545
		var textareaStyles = (historyStorage.debugMode
546
			? 'width: 800px;height:80px;border:1px solid black;'
547
			: historyStorage.hideStyles
548
		);
549
		var textareaHTML = '<form id="' + formID + '" style="' + formStyles + '">'
550
			+ '<textarea id="' + textareaID + '" style="' + textareaStyles + '"></textarea>'
551
		+ '</form>';
552
		document.write(textareaHTML);
553
		this.storageField = document.getElementById(textareaID);
554
		if (typeof window.opera !== "undefined") {
555
			this.storageField.focus();/*Opera needs to focus this element before persisting values in it*/
556
		}
557
	},
558
	
559
	/*Public*/
560
	put: function(key, value) {
561
		this.assertValidKey(key);
562
		/*if we already have a value for this, remove the value before adding the new one*/
563
		if (this.hasKey(key)) {
564
			this.remove(key);
565
		}
566
		/*store this new key*/
567
		this.storageHash[key] = value;
568
		/*save and serialize the hashtable into the form*/
569
		this.saveHashTable();
570
	},
571
572
	/*Public*/
573
	get: function(key) {
574
		this.assertValidKey(key);
575
		/*make sure the hash table has been loaded from the form*/
576
		this.loadHashTable();
577
		var value = this.storageHash[key];
578
		if (value === undefined) {
579
			value = null;
580
		}
581
		return value;
582
	},
583
584
	/*Public*/
585
	remove: function(key) {
586
		this.assertValidKey(key);
587
		/*make sure the hash table has been loaded from the form*/
588
		this.loadHashTable();
589
		/*delete the value*/
590
		delete this.storageHash[key];
591
		/*serialize and save the hash table into the form*/
592
		this.saveHashTable();
593
	},
594
595
	/*Public: Clears out all saved data.*/
596
	reset: function() {
597
		this.storageField.value = "";
598
		this.storageHash = {};
599
	},
600
601
	/*Public*/
602
	hasKey: function(key) {
603
		this.assertValidKey(key);
604
		/*make sure the hash table has been loaded from the form*/
605
		this.loadHashTable();
606
		return (typeof this.storageHash[key] !== "undefined");
607
	},
608
609
	/*Public*/
610
	isValidKey: function(key) {
611
		return (typeof key === "string");
612
	},
613
	
614
	/*Public - CSS strings utilized by both objects to hide or show behind-the-scenes DOM elements*/
615
	showStyles: 'border:0;margin:0;padding:0;',
616
	hideStyles: 'left:-1000px;top:-1000px;width:1px;height:1px;border:0;position:absolute;',
617
	
618
	/*Public - debug mode flag*/
619
	debugMode: false,
620
	
621
	/*- - - - - - - - - - - -*/
622
623
	/*Private: Our hash of key name/values.*/
624
	storageHash: {},
625
626
	/*Private: If true, we have loaded our hash table out of the storage form.*/
627
	hashLoaded: false, 
628
629
	/*Private: DOM reference to our history field*/
630
	storageField: null,
631
632
	/*Private: Assert that a key is valid; throw an exception if it not.*/
633
	assertValidKey: function(key) {
634
		var isValid = this.isValidKey(key);
635
		if (!isValid && this.debugMode) {
636
			throw new Error("Please provide a valid key for window.historyStorage. Invalid key = " + key + ".");
637
		}
638
	},
639
640
	/*Private: Load the hash table up from the form.*/
641
	loadHashTable: function() {
642
		if (!this.hashLoaded) {	
643
			var serializedHashTable = this.storageField.value;
644
			if (serializedHashTable !== "" && serializedHashTable !== null) {
645
				this.storageHash = this.fromJSON(serializedHashTable);
646
				this.hashLoaded = true;
647
			}
648
		}
649
	},
650
	/*Private: Save the hash table into the form.*/
651
	saveHashTable: function() {
652
		this.loadHashTable();
653
		var serializedHashTable = this.toJSON(this.storageHash);
654
		this.storageField.value = serializedHashTable;
655
	},
656
	/*Private: Bridges for our JSON implementations - both rely on 2007 JSON.org library - can be overridden by options bundle*/
657
	toJSON: function(o) {
658
		return o.toJSONString();
659
	},
660
	fromJSON: function(s) {
661
		return s.parseJSON();
662
	}
663
};