代码没有报错，按照老师敲得，看了4.5遍也没找出来错误，为什么没有果实

var fruitObj=function()

{

this.alive=[];

this.x=[];

this.y=[];

this.orange=new Image();

this.blue=new Image();

}

fruitObj.prototype.num=30;

fruitObj.prototype.init=function()

{

    for (var i=0;i<this.num;i++) 

    {

    this.alive[i]=true;

    this.x[i]=0;

    this.y[i]=0;

    this.born(i);

    }

    this.orange.src="./src/fruit.png";

    this.blue.src="./src/blue.png";

}

fruitObj.prototype.draw=function()

{

   for (var i = 0; i<this.num; i++) 

   {

    ctx2.drawImage(this.orange,this.x[i],this.y[i]);

   }

}

fruitObj.prototype.born=function(i)

{

var aneID=Math.floor(Math.random()*ane.num);

    this.x[i]=ane.x[aneID];

    this.y[i]=canHeight-ane.len[aneID];

}