Persist javascript variables between GET requests?

Question

ASP .NET is allowed
Storing the values in hidden input fields is allowed
Query String is not allowed
POST request is not allowed

It is possible to store J

Answer 1

Can I use cookies for this ?

Yes, see this tutorial on using cookies in Javascript.

Are there other posibilities?

If you are not allowed to append anything the URL of your requests, I can't come up with any.

Where cookies are stored when Request is made ?

In the HTTP request header. The aforementioned tutorial will tell you how to read their values from Javascript. On the server side with ASP.Net, you can read cookie values using Request.Cookie["cookieName"] which returns an instance of HttpCookie.