How Does JavaScript Work?


JavaScript is the flagship scripting language for web development, but it’s also used for other types of apps and sites. It’s described as “a high-level, single-threaded, garbage-collected, interpreted (or just-in-time compiled), prototype-based, multi-paradigm, dynamic language with a non-blocking event loop.”

It’s an object-oriented language and a procedural one at the same time, which means it supports both imperative and declarative styles of programming. It’s a cross-platform, client-side programming language, which means it runs on user browsers.

This makes it easy for you to code and test on your device without having to download a special program to run it. It’s also a lightweight language, which doesn’t put too much strain on CPU or RAM.

The core features of javascript are variable declarations, functions and operators. It’s important to know how these work so you can use them effectively.

Variables are used in all languages to store information about things. In JavaScript, you can name them anything you want as long as it follows a few rules. For example, you can’t use spaces in your variable names, and you must use hyphens to separate words. You can read more about naming variables in the MDN documentation.

When a variable is defined, it’s stored in memory for later use. When you start executing your code, JavaScript will go through it line by line and assign a value to each variable in turn. For example, if you have a variable named a with a value of 2, it will assign 2 to that variable when you start executing your code at line number 3.

Functions are another essential part of any programming language. In javascript, you can create and call a function by using the keyword function. Once it’s called, it will return the value of the function that was passed to it as an argument. Functions can take arguments that are values, objects or functions themselves.

There are a lot of different ways to write functions, but they all follow the same structure: function name, parameter list and return value. Functions can have multiple parameters, but they must always be surrounded by parentheses. A function can also return a value or an object, but this must be declared as a return value in the code.

You’ll find many examples of functions in the MDN documentation. The first 40 lessons of our introductory javascript course are free, and the full course is available for a one-time payment.

A key aspect of javascript is its ability to be used in conjunction with HTML and CSS. HTML sets out the logical structure of a webpage, while CSS gives it a beautiful look and feel. JavaScript takes this a step further and makes the site interactive. For example, if you click on a button a message will appear that tells you how many times you’ve clicked.

This is just a small sample of what you can do with javascript, but it’s enough to give you a headstart in the world of web development. Keep learning, and you can master this powerful language in no time.