JavaScript Function Closures Quiz

What is a closure in JavaScript?

• A method to create global variables.

• A way to define a function inside another function.

• A type of variable that can only be used inside a function.

• A function that can access its parent scope even after the parent function has closed.

What happens to local variables when a function is finished?

• They are deleted.

• They become global variables.

• They are stored in memory forever.

• They can be accessed by other functions.

What is the purpose of a self-invoking function?

• To create a function that runs only once.

• To increase the performance of the code.

• To create multiple functions at once.

• To define global variables.

What will happen if you create a variable without a declaration keyword?

• It will be undefined.

• It will cause an error.

• It will be a local variable.

• It will always be a global variable.

How can you protect a variable from being changed by other code?

• By defining it inside a loop.

• By using a closure.

• By using the var keyword.

• By declaring it as a global variable.

What is the lifetime of a global variable?

• Only while the function is running.

• Until the page is discarded.

• Until the variable is deleted.

• Until the browser is closed.

What does the 'this' keyword refer to in a function?

• The current object the function is being executed in.

• The global scope.

• The parent function.

• The first argument of the function.

What is the main issue with using a global counter variable?

• It will cause an error if modified.

• It cannot be accessed by functions.

• Any code can change it without permission.

• It will always be undefined.