Only 5mb in IE8 DOM Local Storage?

Question

According to http://msdn.microsoft.com/en-us/library/cc197062(VS.85).aspx, DOM Local Storage “…allows Web applications to store nearly 10 MB of user data”.

I clear my entire history, made sure that I have nothing stored to window.localStorage, and have the following JS function called on page load:

    function
 LoadLocalStorageData()
    {   
        var
 storage = window.localStorage;
        alert(storage.remainingSpace);      
    }

The JS alert shows "5000000".  What happened to the other 5mb?

Answer 1

sessionStorage?

window.sessionStorage.remainingSpace

Answer 2

As in 5mb for local storage and 5mb for sessions storage is 10mb.