命名空间

管理变量，防止全局污染
使用闭包，管理变量空间

var name = '123123';
var init = (function(){
    var name = 'abc';
    function callName(){
        console.log(name);
    
    }
    return  function(){
        callName();
    }
}());

init();

实现连续调用

var deng = {
    smoke:function (){
       console.log('Deng smoking...');
       return this; 
    },
    drink:function (){
        console.log('Deng drinking...');
        return this; 
     },
}

deng.smoke().drink().smoke();

属性拼接

var deng = {
    wife1:{name:'xiao1'},
    wife1:{name:'xiao2'},
    wife1:{name:'xiao3'},
    sayWife: function(num){
        return this['wife'+num]
    }
}

deng.sayWife(1)

对象枚举
1）直接遍历

var obj ={
    name:'123',
    age:12,
    sex:'male',
     __proto__:{
        lastName:'deng',
    } 
}
for(var prop in obj){  //prop是属性名
    console.log(obj[prop]) ;//枚举里面只能这么写
}
//如果写成，obj.prop会转为 obj['prop']去查找这属性名

2）判断原型

var obj ={
    name:'123',
    age:12,
    sex:'male',
    __proto__:{
        lastName:'deng',
    }
    
}
for(var prop in obj){
    if(obj.hasOwnProperty(prop)){
        console.log(obj[prop]);
    }
}