Client side local storage of data - javascript

I want to store some data client side. Cookies are my first inclination, but they get sent with every request, right? Is there a way to store data without it being transferred? I don't necessarily want to add 10-20k of overhead for every request. Is the only alternative HTML 5 webstorage and how many browsers have adopted that?

html5 storage is widely deployed
HTML5 STORAGE SUPPORT
IE FIREFOX SAFARI CHROME OPERA IPHONE ANDROID
8.0+ 3.5+ 4.0+ 4.0+ 10.5+ 2.0+ 2.0+
you can find out more # http://diveintohtml5.ep.io/storage.html

No, not all cookies get sent with every request. You can check to see if a cookie exists, if not create it, and if so, read it. Cookies are still a good cross-browser option for small amounts of data.

http://fsojs.com supports robust file storage client-side, but only works with Chrome at the moment

As you have mentioned, cookies are an options and so is web storage in the HTML5 spec. There's also the ability to use Flash to store data with the added benefit that this data persists across multiple browsers on the same machine, but the drawback that you'll need a fallback for users who don't have Flash.
Personally, keeping the data on the server (identified by the session id or cookie) would be my way to do it, you have control of the data and don't have to worry about losing it when the user clears their cache or switches machines/devices. It's also the most fault-tolerant because it doesn't rely on browser features and/or plugins (other than perhaps cookies).
One more thing, if you're looking for an abstraction of client-side data storage that uses all of the above (cookies, flash, web storage) check out Evercookie

Related

Is IndexedDb dependent on cookie?

I am working on a prototype where we need to support offline data modification of web application, the application is expected to sync back the data when an internet connection is restored. I have taken a look at various HTML5 in-browser storage option and indexeddb looked like the one I wanted. But I am not sure if the data will be persisted between browser close. Is that possible? One more question if I delete the cookie of the browser, will data in indexedDb will be wiped out? My initial tests shows data gets deleted on cookie clear of browser.
If indexeddb is not a viable option, are there any other alternatives to it which can persist data when internet connection is not available?
As per specification database created with indexedDB should be persistent acrross navigation and browser session.
But current implementation is like persistent cookies. So removal of cookies might remove your database too.
As per google chrome indexedDB is a type of temporary storage.
Chrome: https://developer.chrome.com/apps/offline_storage
For microsoft & firefox it is persitent :
Microsoft: https://msdn.microsoft.com/en-in/hh563494.aspx
Firefox: https://developer.mozilla.org/en-US/docs/Web/API/IndexedDB_API/Basic_Concepts_Behind_IndexedDB
Check supported browsers before use.
http://caniuse.com/#search=indexeddb
It isn't dependent on a cookie, though if you need to know who the user is (likely) you'll probably end up using a cookie of some variety...
As for offline sychronization... I thought about this a lot previously and created a project... The documentation for it is detailed and explains why and how... It may help, or at least give you things to think about. It has very recently been updated to support IndexedDB!
http://forbesmyester.github.io/SyncIt/index.html
In this space there is also RemoteStorage ( they were/are looking at using SyncIt + other bits in the project going forward ), Hood.ie and the commercial FireBase in this field.

LocalStorage limit on PhoneGap

There is usually a limit of 5MB on localStorage on browsers, including iPhone's Safari.
Since PhoneGap has the access higher security privileges including access to other storage mechanisms on the device, in theory they should be able to eliminate the limit of 5MB.
For example, it should be able to get around the usual restrictions by storing the data on a file, etc while keeping the API compatible with localStorage javascript object.
Is this done? Or is PhoneGap limited to the same 5MB?
PhoneGap doesn't do anything out of the ordinary to extend the default limits. On Android, I get 2.5M characters in localStorage (Strings in JavaScript are UTF-16).
You can find default limits for most browsers here: http://dev-test.nemikor.com/web-storage/support-test/
This was helpful in understanding the limitations, and I used the code to create a simplified test PhoneGap app.
PhoneGap has File API that should not be affected by browser local storage limits but don't know if there exist any abstraction to make it behave as HTML5 local storage "backend".
If you want to store a large amount of data you should not do that in localStorage, there are databases and files for that kind of need. localStorage is a key-value datastore, it's use is limited and it should not be "hacked" to fit all needs.
Localstorage is something which is provided by the browser.
Localstorage is not something which is available on a device, either a mobile phone or a desktop, that is leveraged by a browser.
Since it is something which the browser provides there is no way, we can change/increase it using Phonegap since your Phonegap app runs inside the browser.
If you want more storage space, you can use a technique which Phonegap can access like a file storage or SQlLite.

Like php session, js/jquery session is there?

In PHP I can store values in a session I can get until it is destroyed / unset,
Is this possible in jQuery or JS, too?
I need to store client side values to retrieve them in another page.
Use cookies or if you need to store lots of data and don't need compatibility with non-state-of-the-art browsers you could also use HTML5 localStorage.
There is nothing like a session variable directly available in javascript but there are definitely some alternatives to achieve this type of behavior. Two I can think of:
Javascript cookies
As demonstrated on this page you can create and retrieve cookies in javascript.
AJAX
You could use AJAX requests to set and retrieve your session variables from a php file. If you're not familiar with AJAX you can find some decent examples here for the classic javascript approach or in case of jQuery in the jQuery .ajax() docs. This method is probably more reliable because it doesn't depend on the client allowing cookies.
You can use JStorage plugin for this ,JStorage , jStorage makes use of HTML5 local storage where available and userData behavior in Internet Explorer older versions. Webkit SQLite is not supported.Current availability: jStorage supports all major browsers - Internet Explorer 6+, Firefox 2+, Safari 4+, Chrome 4+, Opera 10.50+ , (under 1kB when gzipped)!

Different browser behaviour between localStorage/sessionStorage and cookies

This is not so much a technical question as a question of practice: browser storage doesn't seem to have the same browser behaviour as cookies.
For example:
In Firefox 3.6, sessionStorage is not shared between tabs within the same browser session.
localStorage can never be set to expire, while sessionStorage can never persist.
If a site uses cookies for the session, they are shared between tabs.
If a cookie is set to expire, then it expires after a certain date.
It makes sense that it is not 'like for like', however this means that we may need to mix and match our variable storage solutions depending on need. Your thoughts and opinions on the benefits/pitfalls of either would be appreciated.
Background:
On the website we are currently developing, we decided to implement progressive enhancement using browser storage (sessionStorage and localStorage) with a cookie fall-back. Our reason for doing this is simply as a learning exercise, but moving forward this should help us on mobile platforms and situations where cookies are not usable (we are already storing our assets on a cookie-less domain, so this isn't a motivator).
To do this, we have created a class which has set, get, remove and clear methods which store the application variables within a JSON string (this allows us to group values in a hierarchy). For browsers which don't have a JSON parser we use Crockfords JSON plugin.
At run time the storage class works out if the user's browser supports browser storage, otherwise sets the functions to write to cookies instead. Due to the inconsistencies already highlighted (plus others I am unaware of), this 'like for like' progressive enhancement is actually false.
Edit: Another browser vaguary: if IE 8 is running in IE 7 standards mode it supports localStorage and sessionStorage, where standalone IE 7 does not(!).

Data storage with javascript on clients computer?

Anybody knows ways to store data with javascript clients computer? Except using cookies.
May be there is such lib ?
By the way the data I want to be stored isn't secret if that matters.
You could use HTML 5 Local Storage. It's what the Stack Exchange network uses for global authentication. It's supported only by modern browsers but you could always gracefully fallback to cookies if not supported (IE8+, Chrome, Safari, FireFox 3.6+, and Opera 10.61+ are all supported).
You can use the "normal" js cookie method: http://de.selfhtml.org/javascript/objekte/document.htm#cookie
or if you want to use a lib jquery with cookie plugin: http://www.electrictoolbox.com/jquery-cookies/
If you are talking about database type storage there is google gears and adobe air. These are basically browser plugins that allow you to store data locally on the client. Google have deprecated google gears in favour of the new HTML 5 local storage.

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