[javascript-dev] Navigating Folders... going "up"

I am making a file browser, and jsfolderiter.js has shown me everything I need except the ability to go "up" a folder. Is there a simple property such as foldername.backpath to do this?

For example, if I am in 
C:\Stuff\Junk\

I would like to get
C:\Stuff\

I looked into string manipulation as a workaround, but this brings in problems with being cross-platform because of the differences between Windows and OSX paths.

I hope this is not a silly question, I could not find a reference with the properties of Folder().