aneObj.prototype.draw = function()

{

ctx2.save();

ctx2.globalAlpha = 0.6;

ctx2.strokeStyle = "#3b154e";

ctx2.lineWidth = 20;

ctx2.lineCap = "round";

ctx2.stroke();

for(var i =0 ;i<this.num;i++)

{

ctx2.beginPath();

ctx2.moveTo(this.x[i],canHeight);

ctx2.lineTo(this.x[i],canHeight - this.len[i]);

  }

ctx2.restore();

}

为什么我只能画出一条海葵啊？