this.mask = this.createMask(this.maxWidth, this.mcText1._height, 100);
this.mcText.setMask(this.mask1);
function createMask(w, h, level) {
  var mask = this.createEmptyMovieClip("mask"+level, level);
  with (mask) {
    moveTo(0, 0);
    beginFill(0);
    lineTo(w, 0);
    lineTo(w, h);
    lineTo(0, h);
    lineTo(0, 0);
    endFill();
  }
  return (mask);
}