var smallfish=function () {
   this.x;
   this.y;
   this.angle;
   this.eye=new Image();
   this.fade=new Image();
   this.tail=new Image();
   this.smallfishtail;

for (var i=0;i<8;i++)
{
   this.smallfishtail[i]=new Image();
   this.smallfishtail[i].src="./src/babyTail"+i+".png";
}

这样的话在 this.smallfishtail[i]=new Image();会报错Cannot set property '0' of undefined。怎么定义啊