AS3 under Linux

Hi,

I have never done anything with Actionscript, and do not know much about it.
I want to write a program, that runs in a browser, actionscript/flash seems to be perfect.
As I understand, Actionscript got Object Orientation with Version 3.

But I am on Linux, and on this page I read that ( http://mtasc.org/#as3) that mtasc will not support AS3.

Is there a way to write AS3 programs under Linux?

Thanks!
Nathan