Intrduction to javascript.

Java Script

JavaScript is a client-side scripting language, introduced to “make webpages Interactive”.
Js allows us to create dynamic content for the web. JavaScript is a lightweight scripting language it is open-source and allows cross-platform. It not required compilation and is interpreted with object-oriented capabilities. Also, it works with various other programming languages. And this is the reason for its more use all around the world. Many more popular websites and web applications like Google, Amazon, PayPal, etc use this js. The file extension of a JavaScript filename.js

History of JavaScript

Brendan Eich developed JS in 1995 while working at Netscape Communications, Java, Scheme, and Self, inspired it. As Microsoft became a mortal threat, Netscape started standardization to prevent Microsoft from gaining access to JavaScript and They also partnered with Sun Microsystems (usually called Sun) to break the Microsoft monopoly. The main reason the partnership between Sun and Netscape worked so perfectly was that they both had the same goal. JavaScript was initially called as LiveScript by Netscape and Mocha by Sun. Then they later renamed LiveScript/Mocha as JavaScript.

Why do we need JavaScript?

Going forward in our JavaScript introduction, now we are moving to discuss why we need JavaScript.

Most applications work because of an interaction between a client (user’s device) and a remote server. The client makes requests for data from the server. The server receives the request, processes it and then responds accordingly. The response sent back is in a user readable format and is thus acceptable by the client. But this process takes time as well as resources. Although we usually need this connection, in some projects, Js often helps to avoid it.

JavaScript allows validating the forms without the input of the server, reducing unwanted traffic. It provides wonderful tools for a more interactive and user friendly website. Some of the basic functions of Js are:

Autocomplete: The search box gives suggestions, based on what the user has already typed in.
Form validation: If the users enter wrong while filling a form, JavaScript immediately informs them of the error, avoiding to fill it all again.
Fixes layout issues to avoid the overlapping of elements on the web page.
Adds animation to the page to make it more attractive for users.

How JavaScript Works?

JS is single-threaded. This means that the instructions execute sequentially, one at a time. This is possible with the help of the following components:

The JavaScript Engine
It is a program responsible for the translating source code into machine language and its execution on a CPU. Each modern browser installed with a JavaScript engine. Thus there is no need to download any extra software.

The engine consists of 2 components:

Memory Heap– Memory allocation takes place in this.

Call Stack– When the script calls a function, the interpreter first adds it to the call stack and then starts executing it.

The most used JavaScript Engines include Chrome V8, Firefox’s SpiderMonkey, Safari’s Nitro and Edge’s Chakra.


The JS Engine works inside an environment for more features used at runtime. Although js is single-threaded, the runtime environment consists of a thread pool. It allows js to simultaneously run in the background while the user browses without interrupting the program flow.

Js Event Loop

This mechanism manages all the threads from the thread to pool in the order of their execution i.e. it handles the callbacks. A callback is a piece of code executed when a particular event i.e. when a mouse click occurs.

If the event occurs, the environment puts the callback in the Event Handler under the Event Loop. Callbacks code always executed one at a time.

JavaScript – Prerequisites

JavaScript development requires HTML and CSS, but not for learning to it. You can learn HTML and CSS as you start to understand the basics of JavaScript. it is beneficial if the user is familiar with object-oriented programming concepts.

Features of JS

it supports object-oriented programming concepts.
It is a platform-independent and case- sensitive.
it Provides various in-built functions like alert(), prompt() etc.
Capable of exception handling.
it allows the use of functions with or without any name. the function without name is called an anonymous function.

Js Advantages

Faster Speed
It provides high speed to client-side languages. The various features added to the JavaScript for interactivity helps in boosting the speed.

Ease of Learning
JavaScript is an easy language to learn and implement. If the learner is familiar with other programming languages like C or Java, it is much easier to understand the additional features JavaScript provides

Decreases the Server Load
We avoid server traffic by validating user input on the client side form. It reduces server load, giving its advantage over other web languages.

Regular Updates
The team updates JavaScript annually that provides a more edge to JavaScript. it also makes JavaScript a lot more reliable.

Js Popularity
We use Js almost everywhere on the web. By following the Jtech Complete JavaScript Series you will become an expert in no time.

Js Richin Interfaces
it provides numerous interfaces to make the webpage more interactive.

Js Development
JavaScript saves the compilation time, this results in faster development of web applications.


JS Disadvantages

Different Browser Interpretations
All browsers don’t interpret JavaScript in the same manner. Different browsers often display content differently way.

Js Security Issues
Since JavaScript is a client-side scripting language, people may exploit it for more malicious practices. Due to this reason, some users prefer to disable JavaScript on their devices.

Single Inheritance
Js only supports single inheritance and not multiple inheritances.

Sluggish Bitwise Operation
Js uses 32-bit bitwise operands but 64-bit floating-point numbers. Thus before performing any operation, Js converts the number to 32-bits signed integers. After the operation, it converts them back to 64-bits Jsnumbers. This reduces the speed taken by the script.


At this, we come to the end of our Js Introductions. Now we can tell that we are familiar with the term JavaScript. It allows us to dynamically create and manipulate content and multimedia for web applications. Js helps in supporting and creating some of the best applications that we use worldwide. Suffice it to say, it’s a great scripting language for both beginners, as well as the experts. Get know more with our next blog on JavaScript Architecture.

Intrduction to javascript.
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