Local storage and binding to form fields (extending jQuery)

LocalStorageBinding.js

function PageOptions (pageKey)
	{
	var values = {};
	if (window.localStorage)
		{
		var json = window.localStorage.getItem(pageKey);
		try
			{
			values = JSON.parse(json);
			}
		catch (ignored) {}
		}
	if (!values) values = {};


	this.get = function(key)
		{
		return values[key];
		};
	this.put = function(key, value)
		{
		values[key] = value;
		return this;				
		};
	this.save = function()
		{
		if (!window.localStorage || !JSON || !JSON.stringify) return this;
		var json = JSON.stringify(values);
		window.localStorage.setItem(pageKey, json);
		return this;
		}
	this.applyValue = function(key, element)
		{
		var val = this.get(key);
		if (val) element.val(val);
		return this;
		}
	}
$.fn.saveValue = function(options)
	{
	var name = this.attr('name');
	if (!name || !options || !options.put || !options.save) return this;
	
	var value;
	if (this.is('[type=checkbox]'))
		{
		value = this.prop('checked');
		}
	else
		{
		value = this.val();
		}
	options.put(name, value).save();
	return this;
	};
$.fn.loadValue = function(options)
	{
	var name = this.attr('name');
	if (!name || !options || !options.get) return this;
	var value = options.get(name);
	if (this.is('[type=checkbox]'))
		{
		this.prop('checked', !!value);
		}
	else
		{
		this.val(value);
		}
	return this;
	}
$.fn.bindToOptions = function(options)
	{
	return this.loadValue(options).change(function(){ $(this).saveValue(options); });
	}


// Usage
var options = new PageOptions('unique-code-for-this-page');
$('form input[name=somefield]').bindToOptions(options);
$('form input[name=anotherfield]').bindToOptions(options);