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.orange.width*0.5, this.y[i]-this.orange.height*0.5); }}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];}fruitObj.prototype.update = function(){ var num = 0; for (var i = 0; i < this.num; i++) { if (this.alive[i]) num++; }}當(dāng)我把this.born(i)注釋掉的時(shí)候，果實(shí)會(huì)出現(xiàn)在左上角。不注釋就會(huì)報(bào)錯(cuò)