We are 3 students who interested in game development. We want to develop game for both mobile and desktop(for browsers). Which way we should start? Javascript, flash or unity? Can you recommend frameworks for js or flash?

I'd recommend Unity, unless you're going for a 2D game, in which case I'd recommend Flash (with either the Flixel or Flashpunk libraries).

Kylotan thanks for answer, we want to start with 2D.I will have look at flixel and flashpunk

Isn't flash banned from mobile devices...or lets say not available?

Kylotan, Flixel and Flashpunk havent been updated for 2 years.

MBrain, the quality of software is not necessarily proportional to how recently it was updated. In fact, the opposite is sometimes true - regular updates could indicate lots of bug fixes in a codebase of generally poor quality.

I recommend Flashpunk and Flixel because they are quite stable, proven to work well, and there are decent communities behind them.

I also don't think it matters too much because skills acquired with one technology can be transferred elsewhere fairly easily.

hmm not sure flash and javascript are good routes if you're targeting mobile. desktops are crazy powerful enough to yield decent performance with javascript games but mobile devices are much more constrained and less room for inefficiencies. of the options you listed, i'd go for Unity and give your players a nice steady frame rate :)

There are some nice 2D game tools for Unity. Don't discount it just yet!