Ethan Hughes

Ethan Hughes


JavaScript Event Loop And Call Stack Explained

My goal with this article is to teach you how JavaScript works in the browser. Even though I’ve been working with JavaScript my whole career, I didn’t get how these things work until recently.

I still forget how this works from time to time. That’s why I wrote this article. I hope it will make you understand these concepts as well.

How JavaScript works in the browser

Before I dive into the explanation of each topic, I want you to have a look at this high-level overview that I created, which is an abstraction of how JavaScript interacts with the browser.

Don’t worry if you don’t know what all of the terms mean. I will cover each of them in this section.

High level overview of how JavaScript works in the browser

Note how most of the things in the graphic aren’t part of the JavaScript language itself. Web APIs, the callback queue, and the event loop are all features that the browser provides.

A representation of NodeJS would look similar, but in this article, I’ll focus on how JavaScript works in the browser.


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Buddha Community

JavaScript Event Loop And Call Stack Explained
Gordon  Taylor

Gordon Taylor


How Javascript Is Single Threaded? in-Depth Explaination Of Event Loop and Call Stacks

I started learning Javascript about 2 years ago and wondering to find bits and pieces to explore how it internally works. I’d gotta heard words like v8 runtime engine which runs on browser but didn’t know anything about it and started doing my own research and experiment in the browser. Mostly all JS dev might have heard the term V8, chrome’s Runtime but some might even didn’t really know what that meant, what that did.

First of all, what is Javascript under the hood — the core component of NodeJS. Well, JS is single threaded, single concurrent language which has a call stack, an event loop, a callback queue and some other APIs. If we talk about the v8 runtime in the browser, the below one is simplified view of what it really is…

What is call stack?

You can think call stack to be a functional stack or execution stack when your Javascript code is run line by line. Unless the part of code is handed over to the callback queue, it fills the call stack of a run-time engine.

Consider the following image for the sake of understanding.

Here, first of all JS is designed to be run on the main() thread and so the main() function will be called first when we execute the above code all together. The entry execution point is console.log() statement and the execution will be halted until the argument provided inside does not finish its execution i.e. bar(6). Now, the bar(6) will be pushed on to the stack and then it calls the function foo(3*6) and hence comes on top. Now, when the execution of foo() finishes, it will return the result by popping the entry from stack and comes down to bar(6) which in turn will return entry to the console and it prints the result.

#javascript #event-loop #call-stack #web-development

Lowa Alice

Lowa Alice


JavaScript Loops Tutorial

JavaScript loops made simple.

📺 The video in this post was made by Programming with Mosh
The origin of the article:
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Thanks for visiting and watching! Please don’t forget to leave a like, comment and share!

#javascript #loops #javascript loops #javascript loops tutorial

Hertha  Mayer

Hertha Mayer


Authentication In MEAN Stack - A Quick Guide

I consider myself an active StackOverflow user, despite my activity tends to vary depending on my daily workload. I enjoy answering questions with angular tag and I always try to create some working example to prove correctness of my answers.

To create angular demo I usually use either plunker or stackblitz or even jsfiddle. I like all of them but when I run into some errors I want to have a little bit more usable tool to undestand what’s going on.

Many people who ask questions on stackoverflow don’t want to isolate the problem and prepare minimal reproduction so they usually post all code to their questions on SO. They also tend to be not accurate and make a lot of mistakes in template syntax. To not waste a lot of time investigating where the error comes from I tried to create a tool that will help me to quickly find what causes the problem.

Angular demo runner
Online angular editor for building demo.

Let me show what I mean…

Template parser errors#

There are template parser errors that can be easy catched by stackblitz

It gives me some information but I want the error to be highlighted

#mean stack #angular 6 passport authentication #authentication in mean stack #full stack authentication #mean stack example application #mean stack login and registration angular 8 #mean stack login and registration angular 9 #mean stack tutorial #mean stack tutorial 2019 #passport.js

Rahul Jangid


What is JavaScript - Stackfindover - Blog

Who invented JavaScript, how it works, as we have given information about Programming language in our previous article ( What is PHP ), but today we will talk about what is JavaScript, why JavaScript is used The Answers to all such questions and much other information about JavaScript, you are going to get here today. Hope this information will work for you.

Who invented JavaScript?

JavaScript language was invented by Brendan Eich in 1995. JavaScript is inspired by Java Programming Language. The first name of JavaScript was Mocha which was named by Marc Andreessen, Marc Andreessen is the founder of Netscape and in the same year Mocha was renamed LiveScript, and later in December 1995, it was renamed JavaScript which is still in trend.

What is JavaScript?

JavaScript is a client-side scripting language used with HTML (Hypertext Markup Language). JavaScript is an Interpreted / Oriented language called JS in programming language JavaScript code can be run on any normal web browser. To run the code of JavaScript, we have to enable JavaScript of Web Browser. But some web browsers already have JavaScript enabled.

Today almost all websites are using it as web technology, mind is that there is maximum scope in JavaScript in the coming time, so if you want to become a programmer, then you can be very beneficial to learn JavaScript.

JavaScript Hello World Program

In JavaScript, ‘document.write‘ is used to represent a string on a browser.

<script type="text/javascript">
	document.write("Hello World!");

How to comment JavaScript code?

  • For single line comment in JavaScript we have to use // (double slashes)
  • For multiple line comments we have to use / * – – * /
<script type="text/javascript">

//single line comment

/* document.write("Hello"); */


Advantages and Disadvantages of JavaScript

#javascript #javascript code #javascript hello world #what is javascript #who invented javascript

Peyton  Ullrich

Peyton Ullrich


Easiest Series For Learning Javascript - Javascript Events - Video 15

Read more about javascript events here -

#javascript #learning javascript #javascript events