做项目中总要用到文字滚动条，nshen那个滚动条类不能动态的加入文本，所以放弃使用了，自己写了个scrollClass，感觉还不错。导入scrollClass后，只要在Flash第一楨写
import Billow.util.scrollClass;
var inputText = "asdfasdfasdfasdfasdfasdfasdfasdfasdfasdfasdfasdf";
var scrollSpeed = 4;
var backName = "background_mc";
var barName = "bar_mc";
var dragName = "