为什么果实出不来了 求答案谢谢

var fruitObj=function()

{

this.alive=[];

this.x=[];

this.y=[];

this.orange=new Image();

this.blue=new Image();

}

fruitObj.prototype.unm=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()

{

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

this.x[i] =ane.x[aneId];

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

}