about Focus
FocusEvent.FOCUS_IN— The target received focus.
FocusEvent.FOCUS_OUT— The target lost focus.
To set a custom tab order, use the tabIndex property of the InteractiveObjects you want to be able to tab to. Toremove them from the tab order and restore automatic
tab ordering, reset all thetabIndex properties to their default, -1.
setTimeOut：設置超時時間，只會執行一次！
setInterval：設置一個間隔時間，間隔多久會觸發一次！除非remove，否則會永久執行下去
利用外部庫顯示GIF動畫
One example is the AS3 GIF Player library by Thibault Imbert, available at http://as3gif.googlecode.com/, that lets you display animated GIFs.
關於shareObject
The name of the shared object cannot contain spaces or these characters:
～ % & \ ; : " ‘ , < > ? #.
The first time you try to get the SharedObject with this name, it is created for you, so you don’t have to worry if a SharedObject already exists.
import flash.net.SharedObject;
var hiscores:SharedObject = SharedObject.getLocal("hiscores");