Encapsulation of information in JavaScript Introduction to js objects

Encapsulation of information in JavaScript
Before coding, we need to understand the following terms;
Encapsulation: hiding the representation and implementation details of internal data;
Private properties and methods: only external Can access and interact with it through its public interface
Scope: In JavaScript, only functions have scope, and the properties and methods defined inside the function are not accessible from the outside
Privileged methods: Declared inside the function, they can The method of accessing internal variables (properties) of a function consumes more memory;

function Person() 
{ 
/* 
* 声明私有的数据 
* 昵称，年龄，邮箱 
*/ 
var nickName, age, email; 
/* 
* 需要访问私有数据的方法(特权方法) 
* 每生成一个实例将为特权方法生成一个新的副本 
*/ 
this.setData = function(pNickName, pAge, pEmail) 
{ 
nickName = pNickName; 
age = pAge; 
email = pEmail 
}; 
this.getData = function() 
{ 
return [nickName, age, email]; 
} 
} 
/* 
* 不需要直接访问私有数据的方法（公有方法） 
* 不管生成多少实例，公有方法在内存中只存在一份 
*/ 
Person.prototype = { 
showData: function() 
{ 
alert("个人信息：" + this.getData().join()); 
} 
}

External code accesses internal properties through private or public methods

var p = new Person(); 
p.setData("sky", "26", "vece@vip.qq.com"); 
p.showData();

Demo code:

<script> 
function Person() 
{ 
var nickName, age, email; 
this.setData = function(pNickName, pAge, pEmail) 
{ 
nickName = pNickName; 
age = pAge; 
email = pEmail 
}; 
this.getData = function() 
{ 
return [nickName, age, email]; 
} 
} 
Person.prototype = { 
showData: function() 
{ 
alert("个人信息：" + this.getData().join()); 
} 
} 
var p = new Person(); 
p.setData("PHP中文网", "4", "admin@php.cn"); 
p.showData(); 
</script>

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