zhis

因为 js中 function 是动态绑定zhis

万能公式：谁调用，谁是this，全局中调用，全局对象是this。

• 第一题

var fullname = 'John Doe';
var obj = {
    fullname: 'Colin Ihrig',
    prop: {
        fullname: 'Aurelio De Rosa',
        getFullname: function() {
            return this.fullname;
        }
    }
};

var test = obj.prop.getFullname;
console.log(obj.prop.getFullname());
console.log(test());
//打印，谁调用谁的zhis 。  node环境有 fullname 没有挂载到 globa，所以 undefined
Aurelio De Rosa
John Doe

• 第一.五题

var myObject = {
 foo: "bar",
 func: function() {
     var self = this;
     console.log("outer func: this.foo = " + this.foo);
     console.log("outer func: self.foo = " + self.foo);
     (function() {
         console.log("inner func: this.foo = " + this.foo);
         console.log("inner func: self.foo = " + self.foo);
     }());
 }
};
myObject.func();

//打印
outer func: this.foo = bar
outer func: self.foo = bar
inner func: this.foo = undefined
inner func: self.foo = bar

• 第二题

var obj = {
    x: 10,
    fn: function() {
        function f() {
            console.log(this);
            console.log(this.x);
        }
        f();
    }
};
obj.fn();
//打印
window
undefined

• 第三题

function a(xx) {
    this.x = xx;
    return this
};
var x = a(5);
var y = a(6);
console.log(x.x);
console.log(y.x);
//打印
undefined
6