[daliusd]

Actually QML apps can be written only using QML + Javascript. Performance or platform dependent parts can be written in C++.

Some Qt based frameworks experience. Ubuntu Touch chose to develop apps using Javascript only where possible. BlackBerry apps support both Javascript and C++. There are people who believe that QML must be used only for UI and all logic must be written in C++. IMHO Javascript is good choice as it is fast enough in many cases.

As for Python that's not what you want to use with QML and pure Qt is not what you want to use for mobile apps.

[Aldo_MX]

Javascript in iOS is not a good idea, unless you are just prototyping/building a basic app.

[daliusd]

Maybe. My experience (not Qt based) with Javascript on iOS is not very bad (I expected worse). While I don't like that Apple created fake problems using script languages in iOS.