Is there a better way to embed maps on the iPhone, without using native code?

I have an iPhone application, which does include maps. However, when a user clicks a button in the app - it just brings up an embedded safari browser, with the Google Maps in it. This is because I have a web version of the app, and I want the exact same result on both iPhone and web, without having to constantly update both codes. Also, it includes display of a polygon and pins.

Is there a better way to implement Javascript maps on the iPhone in a native app? Or for Javascript to control a native Google map in the iPhone application?

I don't really fancy the idea of "translating" all the Javascript code, database lookup etc, into native code.

Any ideas?