JavaScript基础-Object类

在JavaScript中Object是所有对象的父类，这和Java一样，也就是说所有的类继承Object，既所有的对象都继承了Object中拥有的方法。

2.构造函数

Object

// Object initialiser or literal
{ [ nameValuePair1[, nameValuePair2[, ...nameValuePairN] ] ] }

// Called as a constructor
new Object([value])
//或者直接这样
var obt = {};

参数

nameValuePair1, nameValuePair2, ... nameValuePairN

value

Object.length

Object.prototype

Object.prototype.

constructor

true

test

Object.prototype.

hasOwnProperty(prop)

in

Object.prototype.isPrototypeOf(object)

Object.prototype.

propertyIsEnumerable(prop)

toLocaleString()

Object.prototype.toString()

Object.prototype.valueOf()

Object.create()

Object.defineProperty()

Object.freeze()

Object.getOwnPropertyDescriptor()

Object.getOwnPropertyNames()

Object.getPrototypeOf()

Object.isExtensible()

Object.isFrozen()

Object.isSealed()

Object.keys()

Object.preventExtensions()

Object.seal()

例子：给定

undefined

和

null

类型使用

Object

Object

o

var o = new Object();

var o = new Object(undefined);

var o = new Object(null);

例子：使用

Object

生成布尔对象

Boolean

o

// 等价于 o = new Boolean(true);
var o = new Object(true);

// 等价于 o = new Boolean(false);
var o = new Object(Boolean());

Examples
Since Javascript doesn't exactly have sub-class objects, prototype is a useful workaround to make a “base class” object of certain functions that act as objects. For example:[code]var Person = function() {this.canTalk = true;this.greet = function() {if (this.canTalk) {console.log('Hi, I\'m ' + this.name);}};};var Employee = function(name, title) {this.name = name;this.title = title;this.greet = function() {if (this.canTalk) {console.log("Hi, I'm " + this.name + ", the " + this.title);}};};Employee.prototype = new Person();var Customer = function(name) {this.name = name;};Customer.prototype = new Person();var Mime = function(name) {this.name = name;this.canTalk = false;};Mime.prototype = new Person();var bob = new Employee('Bob', 'Builder');var joe = new Customer('Joe');var rg = new Employee('Red Green', 'Handyman');var mike = new Customer('Mike');var mime = new Mime('Mime');bob.greet();joe.greet();rg.greet();mike.greet();mime.greet();

Hi, I'm Bob, the BuilderHi, I'm JoeHi, I'm Red Green, the HandymanHi, I'm Mike