Is there a way ActionScript 3 can detect the user\'s screen resolution?
have a look at stage.fullScreenHeight and stage.fullScreenWidth
These will return the numbers to your output window:
trace(Capabilities.screenResolutionX);
trace(Capabilities.screenResolutionY);
If you are on AIR, you could use the flash.display.Screen class, which contains this info, plus a lot more, such as color-depth, and multi-screen support.
flash.system.Capabilities.screenResolutionY and flash.system.Capabilities.screenResolutionX