if (drag) {
  var e = 2.71828; //设置一个弹簧的比例系数
  if (j<1) {
    //根据球的位置，取得变量的值
    y = 2*(getProperty("weight", _y)-yw); 
    j = 1;
  }
  xp = getProperty("dot", _x); //取得要绘制的曲线的点
  yp = getProperty("dot", _y);
  bn = "dot" add i;
  duplicateMovieClip("dot", bn, i); / /复制一个Clip
  setProperty(bn, _x, xp+i); //设置所复制Clip的位置
  setProperty(bn, _y, yp+n);
  //取得绘制曲线时所需的值
  n = y*Math.pow(e, -0.005*i)*Math.sin(0.2*i); 
  im = i;
  i++;
  nx = getProperty(bn, _x); //取得曲线的位置
  if (nx>800) { //判断所绘制的曲线是否到了场景的边缘
    for (m=0; m<=im; m++) {
      cn = "dot" add m;
      removeMovieClip(cn); //删除所绘制的曲线
    }
    gotoAndPlay(1);
  }
}

//设置弹簧的缩放比例
_root.spring._yscale = sp+0.5*(_root.weight._y-yw); 
_root.spring._y = ys+0.375*(_root.weight._y-yw);
if (j>0) {
  _root.weight._y = yw+n; //控制球的运动
  spring._yscale = sp+0.5*n; //改变弹簧缩放比例的值
  spring._y = ys+0.375*n;
}

i=0;
j=0;
dot._x=50;
dot._y=450;
drag=false;

　　在第3帧的Action面板上面增加如下语句：

gotoAndPlay(2);