1 var c=function(){

2    alert(this==window)

3   }

4   c()//true

var myObj={

  value:2,

  inc:function(num){

   alert(this.value+num);

  }

 }

 myobject.inc(1); //结果3，因为this指向myObj

var myObj={

   name:'myObject',

   value:0,

   increment:function(num){

    this.value += typeof(num) ==='number'? num:0;

   },

   toString:function(){

    return '[object:'+this.name+'{value:'+this.value+'}]';

   },

   getInfo:function(){

      return (function(){

        return this.toString();//内部匿名函数不属于当前对象的函数，因此this指向了全局对象window

      })();

  }

 }

alert(myObj.getInfo());//[object window];

 var myObj={

  name:'myObject',

  value:0,

  increment:function(num)   {

   this.value += typeof(num) ==='number' ? num : 0;

  },

  toString:function()   {

    return '[object:'+this.name+'{value:'+this.value+'}]';

  },

  getInfo:function(){

   var This=this;//先把当前的this指向存起来

   return (function(){

      return This.toString();

   })();

  }

 }

alert(myObj.getInfo());//[Object:myObject {value:0}]

 var fn = function (status){

  this.status = status;

 }

 fn.prototype.get_status = function(){

   return this.status;

 }

 var test = new fn('my status');

 alert(test.get_status);//my status,this指向test

function MyObject(name){

   this.name=name ||'MyObject';

   this.value=0;

   this.increment=function(num){

   this.value += typeof(num) === 'number' ? num : 0;

  };

  this.toString=function(){

    return '[Object:'+this.name+' {value:'+this.value+'}]';

  };

   this.target=this;

 }

 function getInfo(){

   return this.toString();

 }

 var myObj=new MyObject();

 alert(getInfo.apply(myObj));//[Object:MyObject {value:0}],this指向myObj

 alert(getInfo.apply(window));//[object Window],this指向window