Go through the fundamentals of JavaScript that interviewers expect you to know, and get plenty of practice along the way.

Ace the Front End Interview

Don't Skip JavaScript

### Explanation

**Option B** is the right answer. The purpose of a call stack is to keep track of all the function calls. Whenever we invoke a function, it is pushed into the call stack first. Once it finishes execution, it gets popped. However, if an asynchronous command enters the call stack, it is popped and added into the task queue, also known as the event queue. Such asynchronous commands include Web Apis callbacks. When the call stack encounters them, it pops them and they enter the task queue instead. The call stack processes these commands once all other commands finish execution, and it is empty. 


>Check out the following [lesson](https://www.educative.io/courses/javascript-interview-handbook/javascript-execution-call-stack-event-loop) to read about this in detail.

**Option A** is incorrect because the roles of the call stack and task queue are opposite in it. **Option C** is incorrect because the call stack does not handle both Web Apis callbacks and function calls. Similarly, **Option D** is incorrect because the task queue does not handle both Web Apis callbacks and function calls.

## Explanation

**Option B** is the right answer. The purpose of a call stack is to keep track of all the function calls. Whenever we invoke a function, it is pushed into the call stack first. Once it finishes execution, it gets popped. However, if an asynchronous command enters the call stack, it is popped and added into the task queue, also known as the event queue. Such asynchronous commands include Web Apis callbacks. When the call stack encounters them, it pops them and they enter the task queue instead. The call stack processes these commands once all other commands finish execution, and it is empty. 


>Check out the following [lesson](https://www.educative.io/courses/javascript-interview-handbook/javascript-execution-call-stack-event-loop) to read about this in detail.

**Option A** is incorrect because the roles of the call stack and task queue are opposite in it. **Option C** is incorrect because the call stack does not handle both Web Apis callbacks and function calls. Similarly, **Option D** is incorrect because the task queue does not handle both Web Apis callbacks and function calls.

In this lesson, we will discuss the solutions to the questions in the previous lesson.

Basics

Event Handling

Asynchronus Callbacks

OOP in JavaScript

Security

Don’t Bomb The DOM

Solution review: Call stack & event loop

Question 1: Solution review #

Explanation #