Question

I have an app with a top frame and two framesets inside this top frame. While navigating to other pages the top frame remains the same and only the framesets change. I use localStorage for storing some data (which is also stored on the server, but if it is on client we don’t make the round trip each time), this feature is not available on IE7 so we decided to try to simulate localStorage in IE7.

The idea was to store a variable localStorage on the top frame (only if localStorage was not available). Whenever localStorage was not available on the top frame we would then create a dummy localStorage object with _data,getItem(),setItem(),removeItem(). The life of this object would last as long as the life of the top frame, which would save us a lot of round trips to the server and therefore offer a great performance boost in IE7.

The problem that I’m having is that whenever I change the frame (not the top frame) and I get the localStorage from the top frame and try to get an item using the window.top.localStorage.getItem(‘…’); I get the error message can’t execute code from a freed script.

Any ideas why I get this??

Answer 1

Maybe I will be repeating what Brilliand already shared, but as I don’t understand his answer entirely I will share some ideas/advice as well:

• First of all make sure that all relevant frames are hosted on the same domain (including things like opening the top frameset on http://www.domain.com and having internal links without the “www.”)
• In case you need cross domain scripting check out the internet for some relevant tricks to achieve that (the theory).
• It might be worth trying to wrap all access to the localStorage within a few functions in the top frame (I can think of a few reasons which could theoretically cause problems with direct access to objects in the top frame… although this should as far as I know work).
• Try reinitialize all references to subframes, you might for example have forgotten adding a “var” in front of a window.frames reference and not reinitalizing it after navigation (it would explain the error message, although it seems quite an unlikely mistake).
• It might be also worth making sure to not keep any references to top.localStorage itself inside any of the child frames (although, again, it shouldn’t cause any problems).
• You might want to consider using a cross platform localstorage wrapper. They tend to work with proprietary functions in IE allowing a localStorage like functionality in IE as well (1MB max, but that should be enough). An example of such a library is store.js