Javascript中两种最通用的定义类的方法

//混合的构造函数/原型方式
//创建对象
function Card(sID,ourName){
    this.ID = sID;
    this.OurName = ourName;
    this.Balance = 0;
}

Card.prototype.SaveMoney = function(money){
    this.Balance += money;
};

Card.prototype.ShowBalance = function(){
    alert(this.Balance);
};

//使用对象
var cardAA = new Card(1000,'james');
var cardBB = new Card(1001,'sun');

cardAA.SaveMoney(30);
cardBB.SaveMoney(80);

cardAA.ShowBalance();
cardBB.ShowBalance();
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//动态原型方法
//创建对象
function Card(sID,ourName){
    this.ID = sID;
    this.OurName = ourName;
    this.Balance = 0;
    if(typeof Card._initialized == "undefined"){
        Card.prototype.SaveMoney = function(money){
            this.Balance += money;
        };

        Card.prototype.ShowBalance = function(){
            alert(this.Balance);
        };
        Card._initialized = true;
    }
}

//使用对象
var cardAA = new Card(1000,'james');
var cardBB = new Card(1001,'sun');


cardAA.SaveMoney(30);
cardBB.SaveMoney(80);

cardAA.ShowBalance();
cardBB.ShowBalance();