var?fruitObj?=?function()
{
	this.alive?=?[];
	this.x?=?[];
	this.y?=?[];
	this.orange?=?new?Image();
	this.bule?=?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.bule.src?=?"./src/bule.png";
}
fruitObj.prototype.draw?=?function()
{
	for(var?i?=?0;i?<?this.num;?i++)
	{
		ctx2.drawImage(this.orange,?this.x[i]?,?this.y[i]);
	}
}
function.prototype.born?=?function(i)
{
	//找到一個位置出生
	var?aneID?=?Math.floor(Math.random()?*?ane.num);//？
	this.x[i]?=?ane.x[aneID];
	this.y[i]?=?canHeight?-?ane.len[aneID];???
}

以下是main.js

var?can1;
var?can2;

var?ctx1;
var?ctx2;

var?canWidth;
var?canHeight;

var?lastTime;
var?deltaTime;

var?bgPic?=?new?Image();
var?ane;
var?fruit;
document.body.onload?=?game;

function?game(){
	init();
	lastTime?=?Date.now();
	deltaTime?=?0;
	gameloop();
}
function?init(){
	//獲得canvas?context
	can1?=?document.getElementById("canvas1");//fishes,dust,UI,circle
	ctx1?=?can1.getContext("2d");
	can2?=?document.getElementById("canvas2");//background,ane,fruits
	ctx2?=?can2.getContext("2d");
	bgPic.src?=?"./src/background.jpg";

	canWidth?=?can1.width;
	canHeight?=?can1.height;
	
	ane?=?new?aneObj();
	ane.init();

	fruit?=?new?fruitObj();
	fruit.init();
}
function?gameloop(){
	window.requestAnimFrame(gameloop);//setInterval,setTimeout,frame?per?second
	var?now?=Date.now();
	deltaTime?=now?-?lastTime;
	lastTime?=?now;
	drawBackground();
	ane.draw();
	fruit.draw();
}