What Is JavaScript?


JavaScript is one of the most popular programming languages in the world. It’s also one of the most versatile, as it can be used to create a wide variety of dynamic web pages and applications.

Initially created to make web pages “alive,” javascript is now used to build everything from social media sites to search engines and apps. It’s also used to create single-page applications (SPAs) that run on a single HTML page.

It’s a client-side language, which means it is run by a user’s browser on their device. It’s also faster than server-side languages and enables web developers to add features that wouldn’t be possible if the code was on the server.

This is especially useful when working with complex pages. It allows you to load parts of the page independently, which can improve speed and memory usage.

You can also use javascript to build extensions for browsers like Google Chrome and Firefox. These allow you to modify browser functionality and add new texts or functionalities, for example. Some of the most popular JS-based browser extensions include Adblock Plus, HubSpot, LastPass and so on.

How it works

JavaScript is a dynamic, interpreted language that is loaded as human-readable source code and compiled into bytecode, which is then fed to an interpreter. The bytecode is then converted to machine code, which is eventually executed on a CPU.

The syntax of javascript is similar to that of other scripting languages, with a particular syntax for declaring constants and variables. It supports multiple programming paradigms, such as object-oriented and functional programming.

Variables are declared using the var keyword, which can be global or block-scoped (accessible only in a certain block of the code). They may contain either fixed values (constants known as literals) or alterable values.

Once declared, a variable can be assigned a value using the var keyword or through a function. In both cases, the value is stored in the variable’s FEC.

Another key feature of javascript is that it has dynamic typing, meaning that it’s able to support a wide range of variable types and assigning rules without the need for compiling the code. Unlike compiled languages, dynamically typed programs are easier to write and test, which is why it’s often preferred by programmers who want to build responsive web pages that automatically adjust to different screen sizes.

It’s also great for detecting user actions, such as touch screen presses, cursor movements, mouse clicks and scrolls. This can help you detect whether a user is active or inactive and store data, such as previous site activity and webpage preferences, on the user’s device.

It’s easy to get started with javascript, but there are a few things you should know before getting started. First, it’s important to know how to write a good script and understand what your goals are. Next, it’s vital to know the difference between a function and a method. Finally, it’s helpful to know about exception handling and error handling.