Document a not ubiquitous pattern.
Upgrade to EcmaScript 5, it's safe and sane. See appendix.

Wondering what the hell "use strict"; is? Look at these articles my
young padawn:
http://ejohn.org/blog/ecmascript-5-strict-mode-json-and-more/
http://www.yuiblog.com/blog/2010/12/14/strict-mode-is-coming-to-town/
Add stackoverflow link to clarify the undefined hack.
Clean out unused variable rootjStorage.
Do some more input checking and have nicer error messages.
Even more documentation