Is there any shared state between iPhone apps and mobile safari?

Question

I have a website and a native iphone app. The app registers a custom protocol. I'd like the site to automatically redirect to the protocol when appropriate, but only if the user has the app installed (to avoid an annoying dialog). That means I need to write some state from the app that I can read in mobile safari to mark the app as installed. Cookies don't seem to exist cross-process. Is there anywhere else I can store my marker?

Answer 1

Look at this blog post to see how Apple does it for the Mobile Me Gallery app. It involves the app opening a website (on your server) in Safari that loads an 'App Installed' cookie into Safari.