JavaScript Function Reference

In JavaScript, the this keyword refers to an object.

Function Object Methods & Properties

Name	Description
apply()	Calls a function with a specified `this` value and an array of arguments
bind()	Returns a function with a specified `this` value
call()	Calls a function with a specified `this` value and individual arguments
length	Returns the number of (expected) parameters of a function
name	Returns the name of the function
toString()	Returns a string representation of the function's source.

In JavaScript, the this keyword refers to an object.

The this keyword refers to different objects depending on how it is used:

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 object method, `this` refers to the object.
In an event, `this` refers to the element that received the event.
In methods like `call()`, `apply()` and `bind()`, `this` can refer to any object.

this is not a variable. > this is a keyword. > You cannot change the value of this.

Use the following precedence of order to determine which object this refers to:

Order	Object	Because
1	bind()	`this` is in a function being called using bind()
2	apply()	`this` is in a function being called using apply()
2	call()	`this` is in a function being called using call()
3	Object method	`this` is in an object function (method)
4	Global scope	`this` is in a function in the global scope

Use the following precedence of order to determine which object this refers to:

Order	Object	Because
1	bind()	`this` is in a function being called using bind()
2	apply()	`this` is in a function being called using apply()
2	call()	`this` in is a function being called using call()
3	Object method	`this` in is an object function (method)
4	Global scope	`this` in isa function in the global scope