Javascript-this

Question 1

What is this in JavaScript?

Answer 1

1. implicit parameter –> this is pointing to an object we want to look at.
   key word that contains a value defined at a call time.

Question 2

What does it mean to say that this is an “implicit parameter”?

Answer 2

1. value that is available in function defintion even though we didn’t put it in a parameter
2. NOT explicitly written in function definition. and it is available in function definition.

Question 3

When is the value of this determined in a function; call time or definition time?

Answer 3

call time

Question 4

What does this refer to in the following code snippet?

Answer 4

There is not definition because we are not in call yet, only in defition time
referring to character object.

Question 5

Given the above character object, what is the result of the following code snippet? Why?

Answer 5

The result will be the string value Its me mario. we are calling from character.

Question 6

Given the above character object, what is the result of the following code snippet? Why?

Answer 6

undefined! because window doesn’t have an object!

this is not gear towards to character anymore.

Question 7

How can you tell what the value of this will be for a particular function or method definition?

Answer 7

You wouldn’t be able to tell because function is not called yet.
by default it will refer to the default object.

Question 8

How can you tell what the value of this is for a particular function or method call?

Answer 8

you look at the object that is on the left