代码写完了，可是不能实现循环生成， 求解这是为什么

// JavaScript Document
var fruitObj = function ()
{
	this.alive = [];
	this.x = [];
	this.y = [];
	this.l = [];
	this.spd = [];
	this.fruitType = [];
	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]= false;
		this.x[i]=0;
		this.y[i]=0;
		this.spd[i] = Math.random() * 0.017 + 0.003;
		this.fruitType[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++)
	{
		//draw
		//find an ane , grow, fly up
		if(this.alive[i]){
			if(this.fruitType[i] == "blue")
			{
				var pic = this.blue;
				}
				else{
					var pic = this.orange;
					}
			if(this.l[i]<=14)
		{
			this.l[i] += this.spd[i] * deltaTime;
			}
			else{
				this.y[i] -= this.spd[i] * 7 *deltaTime;
				}
		ctx2.drawImage(pic,this.x[i]-this.l[i]*0.5,this.y[i]-this.l[i]*0.5,this.l[i],this.l[i]);
		
		if(this.y[i<10])
		{
			this.alive[i] = false;
			}
		    }
		
		}
	}
	
	
	
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];
	this.l[i]=0;
	this.alive[i] = true;
	var ran = Math.random();
	if(ran < 0.3)
	{
		this.fruitType[i] = "blue";
		}
		else
		{
			this.fruitType[i] = "orange";
			}
	
	}

	
function fruitMonitor()
{
	var num=0;
	for(var i = 0; i<fruit.num; i++)
	{
		if(fruit.alive[i]) num++;
	}
	if(num<15)
	{
		sendFruit();
		return;
		}
}
function sendFruit()
{
	for(var i=0 ; i < fruit.num; i++)
	{
		if(!fruit.alive[i])
		{
			fruit.born(i);
			
			return;
			}
		}
	}	
	
fruitObj.prototype.update = function()
{
	var num = 0;
	for(var i = 0; i<this.num;i++)
	{
		if(this.alive[i]) num++;
		}
	}