knadh/localStorageDB — pull request #11 by Asgraf (2012-11-21 15:09:09+00:00)
Title: support for sessionStorage & other storageLike objects

I think it would be pretty good solution.
sessionStorage example:

var lib1 = new localStorageDB("library");//uses localStorage
var lib2 = new localStorageDB("library",sessionStorage);//uses sessionStorage