В приведенном ниже коде, событие
KeyboardEvent.KEY_DOWN, разумеется, может прослушиваться любым наследником класса
EventDispatcher (например,
Sprite,
MovieClip,
Stage).

Код AS3:
package
{
import flash.display.Sprite;
import flash.events.Event;
import flash.events.KeyboardEvent;
import flash.text.TextField;
import flash.text.TextFieldType;
import flash.ui.Keyboard;
[SWF(width="320", height="240", frameRate="24", backgroundColor="#CCCCCC")]
public class Main extends Sprite
{
public function Main()
{
if (stage) init();
else addEventListener(Event.ADDED_TO_STAGE, init);
}
private function init(event:Event = null):void
{
removeEventListener(Event.ADDED_TO_STAGE, init);
var t:TextField = new TextField();
t.border = t.background = true;
t.type = TextFieldType.INPUT;
addChild(t);
t.addEventListener(KeyboardEvent.KEY_DOWN, keyDownHandler);
}
private function keyDownHandler(event:KeyboardEvent):void {
if (event.keyCode == Keyboard.ENTER)
(event.target as TextField).text = "Enter key pressed";
}
}
}