this对象

1、改变this

A：call()方法：

function sayNameForAll(label){
    console.info(label + ":" + this.name);
}

var person1 = {
    name : "Nicholas"
};

var person2 = {
    name = "Greg"
};

var name = "Michale";

sayNameForAll.call(this,"global");       //outputs “global:Michale”
sayNameForAll.call(person1,"person1");   //outputs "person1:Nicholas"
sayNameForAll.call(person2,"person2");   //outputs    "person2:Greg"

B：apply()方法：和call()方法一样，接受两个参数，this的值和一个数组或者类似数组的对象，内含需要被传入函数的参数，不需要像使用call()那样一个个指定参数

function sayNameForAll(label){
    console.info(label + ":" + this.name);
}

var person1 = {
    name : "Nicholas"
};

var person2 = {
    name = "Greg"
};

var name = "Michale";

sayNameForAll.apply(this,["global"]);       //outputs “global:Michale”
sayNameForAll.apply(person1,["person1"]);   //outputs "person1:Nicholas"
sayNameForAll.apply(person2,["person2"]);   //outputs    "person2:Greg"