var name = 'window'
 var person = {
 name :'Alan',
 sayOne:function () {
 console.log(this.name)
 },
 sayTwo:function () {
 return function () {
 console.log(this.name)
 }
 }
 }
 person.sayOne()//Alan
 person.sayTwo()() // window 

var name = "global";

var foo = {
 name: "foo",
 getName : function(){
 console.log(this.name);
 }
}

var bar = {
 name: "bar",
 getName : function(){
 return (function(){
 console.log(this.name);
 })();
 }
}

foo.getName(); //foo
foo.getName.call(bar); //bar
foo.getName.call(this); //global
foo.getName.call(window); //global

(function(){

 console.log(this.name)

}.bind(bar))(); //bar

(function(){

 console.log(this.name)

}.bind())(); //global