No downloadable executable content. You can have an alternative programming language interpreter in your program (now), but it can only run scripts that are already in the application bundle.

It's a reasonable restriction from a user's point of view—you don't want to allow arbitrary code execution that may expose vulnerabilities in badly coded applications. It sucks from a developer's point of view.

> You can have an alternative programming language interpreter in your program (now), but it can only run scripts that are already in the application bundle.

If what you say is true, how come there are other web browsers in the App Store?

Opera loads and executes a page on its own servers before passing the content down to the browser.

Other browsers just wrap the native webkit.

On grounds that Apple bans any non Apple interpreter (which downloads code from the net) to be compiled with iOS SDK. I.e. any JavaScript engine including. It's a pure form of anticompetitive censorship.

In addition to the "no code interpreting code" limitation, I'm pretty sure that there's a more specific "any web browser in-app must be the safari browser" rule. Technically, Mozilla could attempt to release an iOS app that used the Safari rendering engine (and framing it around the FF look and feel, bookmark sync, etc.) but I'm sure that would never happen.