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
I wouldn't highly recommend this, but the other option is to alter the window.name property.
You can save some minor bits of data here, then retrieve them on the next page load.
Pros:
Cons:
Of course if you can exclude all the old browsers, then use Global/Client Session Storage!