Javascript this

this

不同地方有不同意義

• 獨立的this(全域)，指向他的擁有者，就是windows 物件
• 非嚴謹模式下，在function中，是 global 物件
• 嚴謹模式下，在function中，是 undefined
• 在物件 event callback中， 是接收這個event的物件(實際執行callback的物件)，也可解釋為擁有者
• call(),apply()中，this是自己傳入，可以是任意物件

It has different values depending on where it is used:

In a method, this refers to the owner object.
Alone, this refers to the global object.
In a function, this refers to the global object.
In a function, in strict mode, this is undefined.
In an event, this refers to the element that received the event.
Methods like call(), and apply() can refer this to any object.