the way javascript create objects

//新建一个对象。

//第一种，直接创建实例

var dada = new Object();
dada.job = "worker";
dada.married = true;

 //第二种

//替代语法（使用对象 literals）

var james = {
    // add properties to this object!
    job : "programmer",
    married : false    
};

//第三种

//使用对象构造器

//function star (name,age,area) {
    var star = function(name,age,area) {
    //var a = function star (name,age,area) {
        //上面的语句相当于var star = function(name,age,area) {
        //也可以是var a = function star (name,age,area) {,但是这样的话下面创建新对象实例的时候就要用a
        this.name = name;
        this.age = age;
        this.area = area;
        this.birthday = function (){
            //return 2013 - this.age;
            //this.birth = 2013;
            this.birthday =2013- this.age;
        };
    }

//一旦您有了对象构造器，就可以创建新的对象实例

var prince = new star("yujianqi",26,"zhejiang");
    //var prince = new a("yujianqi",26,"zhejiang");
    prince.birthday();
    pname = "my name is" + "" + prince.name +", and my birthday is" + "" +prince.birthday +".";
    alert(pname);
    var baby = new star("baby",5,"beijing");
    //您可以通过为对象赋值，向已有对象添加新属性
    baby.married = true;
    baby.birthday();

//JavaScript for...in 语句循环遍历对象的属性。注释：for...in 循环中的代码块将针对每个属性执行一次。

for(a in baby){
        //alert(baby[a]);
        //alert(a);
    }