as3加载 外部txt文件

1、做二个按钮 上up_btn，下down_btn

2.动作：

var external_txt:TextField = new TextField();//创建显示文本的文本框
var externalReq:URLRequest = new URLRequest("1.txt");
var externalLoad:URLLoader = new URLLoader();

externalLoad.load(externalReq);

externalLoad.addEventListener(Event.COMPLETE, textReady);
up_btn.addEventListener(MouseEvent.CLICK, scrollUp);
//对滚动条按钮添加侦听;
down_btn.addEventListener(MouseEvent.CLICK, scrollDown);

external_txt.x = 175;//设置文本框的属性
external_txt.y = 100;
external_txt.border = true;
external_txt.width = 200;
external_txt.height = 200;
external_txt.wordWrap = true;

addChild(external_txt);

function textReady(event:Event):void
{
 external_txt.text = event.target.data;//将读取的文本数据，赋值给文本框
}

function scrollUp(event:MouseEvent):void
{
 external_txt.scrollV--;//实现滚动
}

function scrollDown(event:MouseEvent):void
{
 external_txt.scrollV++;
}