var one = {

    name:"object",

    say:function(greet) {

        return greet + ","+this.name;

    }

}

//console.log(one.say("hi"));  //结果hi,object

var two = {

    name:"another"

};

console.log(one.say.apply(two,["hello"]));  //结果hello,another

//给变量赋值，“this”将会指向全局变量

var say = one.say;

console.log(say("you")); //结果you,undefined

//作为回调函数使用

var yetanother = {

    name:"yet",

    method:function(callback){

        return callback("HOHO");

    }

}

console.log(yetanother.method(one.say));//结果HOHO,undefined

function bind(o,m){

    return function(){

        return m.apply(o,[].slice.call(arguments));

    }

}

var twoSay = bind(two,one.say);

console.log(twoSay("jie"));  //jie,another