Not Getting Key Code for ALT key

Hi,

I am having some trouble in getting key code for alt key. Can Any one help in it.

I am sharing for source code the way I am trying to do it.

import flash.events.KeyboardEvent;

stage.addEventListener(KeyboardEvent.KEY_DOWN, function(e:KeyboardEvent){trace("Key== "+e.keyCode); txt.text=""+e.keyCode;});