JS creates objects (common methods)_js object-oriented

贴个代码先:
function O(user,pwd){ //use constructor
this.user=user;
this.pwd=pwd;
this.get=get;
return this;
}
function O2(user,pwd){ //use factory
var obj=new Object();
obj.user=user;
obj.pwd=pwd;
obj.get=get;
return obj;
}
function O3(){ //use prototype
}
O3.prototype.user='abc';
O3.prototype.pwd='dis';
// O3.propotype.get='get';
//O3.prototype.get(){
//alert(this.pwd);
//}
function O4(user,pwd){
this.user=user;
this.pwd=pwd;
return this;
}
O4.prototype.get=function(){alert('123');}

//function get(){
//alert("This User:" this.user);
// }
function test2(){
//var a=new O2('Us','Pw'); use factory & constructor
//var a=new O3(); //use prototype
//a.get();
var a=new O4('*U4','P4'); //混合
//a.user='Not ABC'; //set new property
//alert(a.user);
a.get();
}
常用的MS 就这几种,可能还有其它的.碰到再说吧....
题外话：昨天手欠，试图用alert(window.appName)到ff之下去查看浏览器版本，结果弹出的竟然是Netscape，咋不是 firefox。继而又跑去chrome下试验，又一次弹出了Netscape。baidu搜 Netscape 竟然发现js就出自Netscape公司。惭愧啊惭愧！！！研究了这么久的js都不认识祖师爷。于是又跑去找了找族谱，原来js出自Brendan Eich之手，95年他创造js时候，也不过就31岁。哎呀，真是白活了，如他一般老的我，到现在都学不会js，真是人比人气死人。。js当初设计的时候，没有想到自己能从一部打电话用的手机变成集拍照，上网，游戏，电话于一身的智能机。真是造化弄人！！！也许各中的神奇，连Brendan Eich本人都没有想到。应该说Brendan Eich创造了js，而一大批的js牛人成就了今天如此复杂的js。
js不是木有类么？没关系，人家不是设计了原型属性么~
js不是木有块级作用域么？没关系，人家不是有作用域链么~
js怎样实现成员变量私有化？哦，用闭包解决吧~
哦，这么多基本概念，彻底的晕掉了，路漫漫其修远兮。
言归正传，本文讨论几种js创建对象的方法，先从最好理解的工厂模式开始：

复制代码 代码如下:

function createPerson(name,age,job){
var o = {};
o.name = name;
o.age = age;
o.job = job;
o.sayName = function(){
alert(this.name);
};
return o;
}
var tanya = createPerson("tanya","30","female");
var ansel = createPerson("ansel","30","male");
tanya.sayName();
ansel.sayName();

这里先定义o为一个空的对象，然后为o设置了一堆属性。其实也可以直接给o属性的嘛，所以如果这样写也是ok的。

复制代码 代码如下:

function createPerson(name,age,job){
var o = {
name : name,
age : age,
job : job,
sayName : function(){
alert(this.name);
}
};
return o;
}
var tanya = createPerson("tanya","30","female");
var ansel = createPerson("ansel","30","male");
tanya.sayName();
ansel.sayName();

还有一种办法是利用无敌的this，因为this就表示当前运行时的对象，将构造函数this的作用域指向新对象，将当前运行对象的属性和方法都赋给新对象，这样对象模式称为构造函数模式

复制代码 代码如下:

function Person(name,age,job){
this.name = name;
this.age = age;
this.job = job;
this.sayName = function(){
alert(this.name);
};
}
var tanya = new Person("tanya","30","female");
var ansel = new Person("ansel","30","male");
tanya.sayName();
ansel.sayName();

在这个例子中，tanya和ansel都有一个constructor属性，该属性指向person。
考虑一下如下的情况：

复制代码 代码如下:

function Person(name,age,job){
this.name = name;
this.age = age;
this.job = job;
this.sayName = function(){
alert(this.name);
};
}
Person("tanya","30","female");
Person("ansel", "30","male");
window.sayName();
window.sayName();

I found that both ansel pops up, this is because new is not used If so, it is not an instance of person, but only executing the function. When calling a function in the global scope, this always points to the Global object. The Global object is the window object in the browser.
We can also use construction mode to call the sayName method in another object. Remember Apply and call. Let’s consider another situation.

Copy Code The code is as follows:

function Person(name,age,job){
this.name = name;
this.age = age;
this.job = job;
this.sayName = function(){
alert(this.name);
};
}
var olivia = {};
Person.call(olivia,"tanya","30","female");
olivia.sayName();
var philip = {}
Person.apply(philip,["ansel" ,"30","male"]);
philip.sayName();

Prototype mode requires considering the prototype chain. After analysis, the sayName method is repeatedly defined in the instance. Twice, but there is no need to create two identical copies. Using the prototype method, tanya and ansel can share a sayName method.
So the prototype pattern is written as follows:

Copy the code The code is as follows:

function Person (name,age,job){
this.name = name;
this.age = age;
this.job = job;
}
Person.prototype.sayName= function( ){
alert(this.name);
};
var tanya = new Person("tanya","30","female");
var ansel = new Person("ansel ","30","male");
tanya.sayName();
ansel.sayName();

In actual application, a certain pattern is not always applied. Learn and apply. Use prototype mode when you need to share methods, and use construction mode when you need to use copies. You can also combine them to encapsulate all information in the constructor, and initialize the prototype in the constructor so that the object can be used simultaneously. Advantages of constructors and prototypes.

Copy code The code is as follows:

function Person(name,age,job){
this.name = name;
this.age = age;
this.job = job;
if (typeof sayName != "function" ){
Person.prototype.sayName= function( ){
alert(this.name);
};
}
}
var tanya = new Person("tanya","30","female");
var ansel = new Person("ansel","30","male");
ansel.sayName = function () {
alert("Hi ansel, how hansome you are!");
}
tanya.sayName();
ansel.sayName();