Learn JavaScript from Scratch JavaScript for Everyone - JavaScript Closures

The video tutorial explains how to create and execute functions in JavaScript, focusing on variable access and closures. It highlights the importance of understanding variable scope, especially when using 'var' inside functions. The tutorial also discusses potential pitfalls when dealing with closures and encourages viewers to practice by creating variables outside and inside functions to observe their behavior.

What is a key feature of functions in JavaScript that allows accessing variables from outside the function?

• Inheritance

• Encapsulation

• Closure

• Polymorphism

In JavaScript, what is a closure?

• A function that returns another function

• A function that can access variables from its parent scope

• A function that is defined inside a loop

• A function that is immediately invoked

Why can't a variable defined inside a function be accessed outside of it?

• Because it is declared with 'var'

• Because it is scoped to the function

• Because it is not declared with 'let'

• Because it is not a global variable

What happens if you try to access a variable defined inside a function from outside the function?

• It will return undefined

• It will throw a reference error

• It will return null

• It will access the global variable with the same name

What is a potential downside of using closures in JavaScript?

• They can make it difficult to track where variables are coming from

• They prevent the use of global variables

• They can lead to memory leaks

• They make code execution slower