how to create an app with Javascript

Answer 1

you need DroidScript or Phonegap.

Answer 2

You can use Unity

Answer 3

The scope of the question is to broad. First you need to learn the scripting language and understand it's limitations.

Then you need to assess if JavaScript if the right language for the app you want to build. if yes then you needed to split the bigger problem into smaller chunks, problems that can be solved individually.

How do you eat an elegant?
Piece by piece

Answer 4

is it possible to code an app without phonegab and other frameworks