About Object

   An object is very similar to the array,but with the differences that you define the keys by yourself.So you are not limited to using only numbers but every keys that you liked.

  An object always contain elements/properties/methods/other objects

1、 defines

  var init = {

   name:'Kitty'

   ,age: 20,

   ,author:{

      firstname:'hello'

      ,lastname:'kitty' 

 }

   ,msg : function(){

      return 'I am '+this.name+',I am old'+this.age;// can call an object's property

}

};

init.school = 'FAFU';

init.class = 3;

init.say = function(){return init.name};

如果没有定义这个属性，则结果是undefined。

 

使用：init.name;/init.say()....

2、Using Constructor Functions to create object

  function Person(name,age){

    this.name = name;

    this.age = age;

    this.say = function(){

    return 'I am '+this.name+',I am old'+this.age;

}

};

  var p = new person('kitty',23);

Note:Declaring a constructor function and calling it without new, returns "undefined":

like: var kitt = Person('kitty',23);

       typeof kitt;//output undefined

3、comparing objects

  var s = {name:'kitty'};

var h = {name:'kityy'};

 s === h;//return false

var l = s;

s === l//return true