flash on 2009-8-1

/**
 * Copyright hacker_9p8x8mco ( http://wonderfl.net/user/hacker_9p8x8mco )
 * MIT License ( http://www.opensource.org/licenses/mit-license.php )
 * Downloaded from: http://wonderfl.net/c/9xim
 */

package{
  import flash.display.*;
  import flash.text.*;
  import flash.utils.setInterval;

  public class HelloWorld extends Sprite{
    public function HelloWorld(){
      var tf:TextField = new TextField();
      tf.text = "Hello World!";
      addChild(tf);

      var str:String = tf.text;
      var len:int = 0;

      setInterval(function():void{
        tf.text = str.substr(0, len);
        len = (len % str.length) + 1;
      }, 100);
    }
      }
}