Top 10 JavaScript Concepts Every Developer Should Know

Emma Delaney
5 min readOct 3, 2023

JavaScript is used on millions of websites and isn’t going away anytime soon. On the one hand, HTML and CSS provide the website’s style, but the magic of JavaScript brings your website to life. A single language can do both, which is why there are so many open positions for JavaScript developers in the IT industry. Be it a small startup or a large company, most of them are developing a website or application that requires in-depth knowledge of this language.

JavaScript has several frameworks. and libraries available. But first, let’s look at some basic JavaScript concepts that every developer should understand.

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1). Asynchronous Communication

Asynchronous communication, also known as AJAX (asynchronous Javascript and XML), plays a vital role in the design and functionality of modern websites.

AJAX It gives you the opportunity to dynamically load information onto your website without having to refresh the entire page. The advantage is that less data is sent from the server when only a section of the page needs to be changed. It also improves the user experience with faster loading times and the page doesn’t flicker every time something changes.

2) Dom Creation & Modification

The ability to create or edit elements on a web page allows you to create dynamic web pages that can change based on user interaction.

3) Loops

Loops are a key element of any programming language. Loops let you repeat blocks of code as many times as you want, so you don’t have to write repetitive code. Loops also allow you to iterate through data structures with minimal effort. Understanding how, when and why to use loops is an essential skill for any programmer.

4) Debugging development tools

All Web browsers have some sort of developer tool for debugging, even the one you’re currently using. If you’re using Chrome, right-click and select Inspect. You should see a “panel” at the bottom or right of the browser.

These are the developer tools, and as mentioned above, all browsers have a module or another. of them, to help developers debug their code. There you will find all the information about the page/site, including information about HTML, CSS and of course Javascript. The ability to use development tools to debug code should be a skill you develop from the beginning.

5) Scope

Maybe one one One of the hardest concepts for a new developer to understand is scope, and it’s an important concept to understand. There are two main types of public relations: global and local. When a variable is declared outside a function, it is considered global and accessible from virtually anywhere in the code. A variable declared in a function is considered local and can only be accessed within that function.

This is scope in its most basic form. And it can quickly become so much more. complex, but understanding these concepts as early as possible can help you build a solid foundation to advance on your journey to becoming a web developer.

6) Features and Functions Calls

Functions, like loops, are a fundamental and universal programming concept in most programming languages. Functions allow you to encapsulate blocks of code that can be used later by calling the function.

7) Conditional Statements

Conditional Statements These they are the basis of all logic/decision making that occurs in the code. If something is true, do it; If not, do this. Every decision made in your code is made using some type of conditional statement. This allows you to control what your code does based on different circumstances and variables.

8) Events and event handling

Most, if not all, of the code executed by a web page is triggered by some type of event. Some of the most common events are: page load, click, mouseover, etc.

Understand the different events in Javascript and when they occur. Activation is an essential skill for any Javascript developer.

Read More: Frequently Asked Questions: Interview Questions for JavaScript

9) Referencing variables, values ​​and data types

Programming it’s all about data manipulation. and the treatment to be carried out. Variables contain this data. (Remember high school algebra? x = y + 3). X and Y are variables that can represent any number. While programming, we use variables to store data in different formats such as: B. Numbers, strings and boolean values.

These are considered as value of variables. Another type of variables are arrays and objects, which in the simplest sense are containers containing groupings of other variables (think of a carton of eggs as an array, and each egg is a variable containing a certain type of data). Arrays and objects are reference variables. Understanding the difference between different variables and data types can help you build a solid foundation for your journey to becoming a developer.

10) Overcome the DOM: with what Javascript?

Javascript was (originally) intended to improve the user experience of a web page, essentially adding a series of details. Javascript gives us the ability to dynamically change our page based on user interaction, creating a more satisfying and meaningful experience for the user. Nowadays, Javascript is used to create web applications and even web games which can be quite complex and engaging. Javascript is a powerful tool for web developers, but none of that matters if you can’t traverse the DOM.

The DOM (Document Object Model) is essentially a tree structure that represents all the HTML elements that make up your web page. Understanding how to navigate (navigate) the DOM using Javascript is undoubtedly one of the most important basic skills required. As mentioned above, Javascript aims to improve the user experience by dynamically modifying the page based on his wants and needs. This isn’t possible if you don’t know how to access a p tag nested in a div with a parent content ID.