//1.函数预编译过程中 this --> window
//AO this: window
function test() {
console.log(this)
}
test() //window
//2.全局作用域里 this --> window
//GO this: window
console.log(this) //window
//3.call/apply可以改变函数运行时this指向
var obj = {}
function Person(name, age) {
this.name = name
this.age = age
}
Person.call(obj, 'lyj', 18)
// Person.apply(obj, ['lyj', 18])
console.log(obj) //{name: "lyj", age: 18}
//4.obj.func(), func()里面的this指向obj
var obj = {
a: function() {
console.log(this.name)
},
name: 'abc'
}
obj.a() //abc
\
var name = '222'
var a = {
name: '111',
say: function() {
console.log(this.name)
}
}
var fun = a.say
fun() //222 没有被谁调用， this指向window
a.say() //111 被a调用， this指向a
var b = {
name: '333',
say: function(fun) {
fun() //没有被谁调用， fun里面的this指向window
}
}
b.say(a.say) //222
b.say = a.say
b.say() //333 被b调用， this指向b
