private function test() : void {
var canvas :Canvas = new Canvas();
canvas.width = 100;
canvas.height = 100;
// 保存到ByteArray
var b : ByteArray = new ByteArray();
b.writeObject(canvas);

// 取出對象
b.position = 0;
var o : Object = b.readObject();
var c : Canvas = objectToInstance(o,Canvas) as Canvas;
trace(c.width);
trace(c.height);
this.addChild(c);
}