adds session storage option

[MatthewVita]

No description provided.

[booleanbetrayal]

@MatthewVita - rather than rename the localStorage check to hasModernStorageSupport checking both, we should have an independent check for sessionStorage.

The reason being, calling getItem on localStorage will cause exceptions if localStorage is unavailable in Safari. In your implementation, the hasModernStorageSupport check could fall-through to sessionStorage, and then during the retrieval call, we still try to call localStorage.getItem and if that returns null it'd proceed. Only ... it'd blow up at that point. Make sense?

[MatthewVita]

@booleanbetrayal very good point. I'd be happy to make the change but first I'd like to explore the following:

Can we prove that it is possible for sessionStorage to be in place and localStorage to not be? Same question applies inversely, of course.

AFAIK, The Web Storage API "defines [these] two types of storage areas" [0]. Perhaps we can conclude that the spec says that both sessionStorage and localStorage are required for a correct implementation of Web Storage API, but browsers can provide overrides to disable one or the other?

[0] http://www.sitepoint.com/an-overview-of-the-web-storage-api/

[booleanbetrayal]

I wouldn't bother making assumptions about browser implementations @MatthewVita . I've seen too much deviance from expectation along those lines with the Storage API, particularly in iOS Safari. Better to just have the separate checks. Let me know when that lands and I'll merge it!

[MatthewVita]

Good call. How that amend look?

[booleanbetrayal]

looks great. thanks @MatthewVita !