dhtmlhistory.js

This is the script which used on 10minutemail.com for temporary email.

	this.listener.call(null, newHash, historyData);
},

/** Sees if the browsers has changed location.  This is the primary history mechanism
	for Firefox. For Internet Explorer, we use this to handle an important edge case:
	if a user manually types in a new hash value into their Internet Explorer location
	bar and press enter, we want to intercept this and notify any history listener. */
/** private */ checkLocation: function() {
	// ignore any location changes that we made ourselves
	// for browsers other than Internet Explorer
	if (this.isInternetExplorer() == false
		&& this.ignoreLocationChange == true) {
		this.ignoreLocationChange = false;
		return;
	}
	
	// if we are dealing with Internet Explorer
	// and we are in the middle of making a location
	// change from an iframe, ignore it
	if (this.isInternetExplorer() == false
		&& this.ieAtomicLocationChange == true) {
		return;
	}
	
	// get hash location
	var hash = this.getCurrentLocation();
	
	// see if there has been a change
	if (hash == this.currentLocation)
		return;
		
	// on Internet Explorer, we need to intercept users manually
	// entering locations into the browser; we do this by comparing
	// the browsers location against the iframes location; if they
	// differ, we are dealing with a manual event and need to
	// place it inside our history, otherwise we can return
	this.ieAtomicLocationChange = true;
	
	if (this.isInternetExplorer()
		&& this.getIFrameHash() != hash) {
		this.iframe.src = "blank.html?" + hash;
	}
	else if (this.isInternetExplorer()) {
		// the iframe is unchanged
		return;
	}
		
	// save this new location
	this.currentLocation = hash;
	
	this.ieAtomicLocationChange = false;
	
	// notify listeners of the change
	this.fireHistoryEvent(hash);
},  

/** Gets the current location of the hidden IFrames
	that is stored as history. For Internet Explorer. */
/** private */ getIFrameHash: function() {
	// get the new location
	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;
},		

/** Removes any leading hash that might be on a location. */
/** private */ 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;	
},		

/** For IE, says when the hidden iframe has finished loading. */
/** private */ iframeLoaded: function(newLocation) {
	// ignore any location changes that we made ourselves
	if (this.ignoreLocationChange == true) {
		this.ignoreLocationChange = false;
		return;
	}
	
	// get the new location
	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);
	
	// move to this location in the browser location bar
	// if we are not dealing with a page load event
	if (this.pageLoadEvent != true) {
		window.location.hash = hash;
	}

	// notify listeners of the change
	this.fireHistoryEvent(hash);
},

/** Determines if this is Internet Explorer. */
/** private */ isInternetExplorer: function() {
	var userAgent = navigator.userAgent.toLowerCase();
	if (document.all && userAgent.indexOf('msie')!=-1) {
		return true;
	}
	else {
		return false;
	}
}
};












/** An object that uses a hidden form to store history state 
	across page loads. The chief mechanism for doing so is using
	the fact that browser's save the text in form data for the
	life of the browser and cache, which means the text is still
	there when the user navigates back to the page. See
	http://codinginparadise.org/weblog/2005/08/ajax-tutorial-saving-session-across.html
	for full details. */
window.historyStorage = {
/** If true, we are debugging and show the storage textfield. */
/** public */ debugging: false,

/** Our hash of key name/values. */
/** private */ storageHash: new Object(),

/** If true, we have loaded our hash table out of the storage form. */
/** private */ hashLoaded: false, 

/** public */ put: function(key, value) {
	this.assertValidKey(key);
	
	// if we already have a value for this,
	// remove the value before adding the
	// new one
	if (this.hasKey(key)) {
		this.remove(key);
	}
	
	// store this new key
	this.storageHash[key] = value;
	
	// save and serialize the hashtable into the form
	this.saveHashTable(); 
},

/** public */ get: function(key) {
	this.assertValidKey(key);
	
	// make sure the hash table has been loaded
	// from the form
	this.loadHashTable();
	
	var value = this.storageHash[key];

	if (value == undefined)
		return null;
	else
		return value; 
},

/** public */ remove: function(key) {
	this.assertValidKey(key);
	
	// make sure the hash table has been loaded
	// from the form
	this.loadHashTable();
	
	// delete the value
	delete this.storageHash[key];
	
	// serialize and save the hash table into the 
	// form
	this.saveHashTable();
},

/** Clears out all saved data. */
/** public */ reset: function() {
	this.storageField.value = "";
	this.storageHash = new Object();
},

/** public */ hasKey: function(key) {
	this.assertValidKey(key);
	
	// make sure the hash table has been loaded
	// from the form
	this.loadHashTable();
	
	if (typeof this.storageHash[key] == "undefined")
		return false;
	else
		return true;
},

/** Determines whether the key given is valid;
	keys can only have letters, numbers, the dash,
	underscore, spaces, or one of the 
	following characters:
	!@#$%^&*()+=:;,./?|\~{}[] */
/** public */ isValidKey: function(key) {
	// allow all strings, since we don't use XML serialization
	// format anymore
	return (typeof key == "string");
	
	/*
	if (typeof key != "string")
		key = key.toString();
	
	
	var matcher = 
		/^[a-zA-Z0-9_ \!\@\#\$\%\^\&\*\(\)\+\=\:\;\,\.\/\?\|\\\~\{\}\[\]]*$/;
					
	return matcher.test(key);*/
},




/** A reference to our textarea field. */
/** private */ storageField: null,

/** private */ init: function() {
	// write a hidden form into the page
	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");
},

/** Asserts that a key is valid, throwing
	an exception if it is not. */
/** private */ assertValidKey: function(key) {
	if (this.isValidKey(key) == false) {
		throw "Please provide a valid key for "
			+ "window.historyStorage, key= "
			+ key;
	}
},

/** Loads the hash table up from the form. */
/** private */ loadHashTable: function() {
	if (this.hashLoaded == false) {
		// get the hash table as a serialized
		// string
		var serializedHashTable = this.storageField.value;
		
		if (serializedHashTable != "" &&
			serializedHashTable != null) {
			// destringify the content back into a 
			// real JavaScript object
			this.storageHash = eval('(' + serializedHashTable + ')');  
		}
		
		this.hashLoaded = true;
	}
},

/** Saves the hash table into the form. */
/** private */ saveHashTable: function() {
	this.loadHashTable();
	
	// serialized the hash table
	var serializedHashTable = HTML_AJAX_JSON.stringify(this.storageHash);
	
	// save this value
	this.storageField.value = serializedHashTable;
}
};

/** Initialize all of our objects now. */
window.historyStorage.init();
window.dhtmlHistory.create();