I'm trying to position a div in the center of the iphone viewport.
Basically so that when you hit an image, it pops up in the middle of the screen regardless of where you had scrolled to on the page before you clicked.

It's not as simple as just making it position: fixed; as that will cause the origin to be the top of the page, not the top of the viewport.

I also can't do something like detecting scroll events and keeping a track of where I'm currently scrolled to, as the Javascript I'm writing is only injected into the page and executed when the popup is triggered.

Is there an iPhone specific JavaScript API or something I can use to get the current viewport coordinates?

Thanks,
Toby