vCard export - client side

I've written this function for contact that returns a VCF-ready string.  VCF (or vCard) is basically the standard file type for contact info, so the idea here is that our users can export their xTuple contacts to their google accounts or their phones or anything, really.  Scroll to the bottom of the 1st panel on a client and click the VCF button under export and check it out in your console.

The problem is, you don't have access to the machine from browser-side javascript.  So, I need the help of a node wizard to get the file saving part down.  It sounds like this is very feasible if you're on a desktop computer, but I'm concerned about whether or not it'll be possible on iphones etc.  Some people on stackoverflow were saying we'd need phonegap to be able to do that stuff, which I know we're not trying to do.