JFStorage: Cookies Alternative

Inspired by Topics Alternative to cookies via java script

The use of cookies is limited to 4 kb. size, they are also visible to the user.
When using Flash Storage, reading cookies is a bit more complicated and allows you to store up to 100 kb and above data on the user's computer.

Management is very simple:

setCookie(key,value) -
getCookie(key) -
removeCookie(key) -
isExistCookie(key) - ?

Size: 3 kb.
Demo: jfstorage.agrr.org/JFStorage.html
Google Code: code.google.com/p/jfstorage

Technology

The part working with SharedObject is taken from ntt.cc/2008/07/13/the-source-code-of-actionscript-3-cookie-class-enables-you-to-read-write-and-edit-shared-objects- on-the-user-hard-disk.html and a bit processed file.
The interaction between javascript and flash is written by me. Standard libraries used.
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How can I use?

As a repository of hidden data.
Like big data storage.
As a way of offline data loading.