ECMASCRIPT

ECMAScript is a standardized specification for a general-purpose scripting language. It is best known as the foundation upon which JavaScript is built. In easy words ECMASCRIPT is the community that collaborate and work on the improvements and enhancements of the language and versions. Nowadays, JS have ECMASCRIPT versions from ECMASCRIPT 1, 1997 to ECMASCRIPT 6, 2015. The improvements edition released yearly, currently ECMASCRIPT 2025 released in June 2025

let x = "Hello";             
let result = x + " World!";   
console.log(result);

Introduction to JS

JavaScript is the programming language of the Web. JavaScript is easy to learn. It is basically used to add functionality in the web. It is the top most language which which were important to learn every developer.

let x = "Hello";             
let result = x + " World!";   
console.log(result);

Why Study JavaScript?

JavaScript is one of the 3 languages all web developers must learn:
1. HTML to define the content of web pages
2. CSS to specify the layout of web pages
3. JavaScript to program the behavior of web pages

let x = "Hello";             
let result = x + " World!";   
console.log(result);

What is JavaScrip?

JavaScript is the programming language of the web.
It can calculate, manipulate and validate data.
It can update and change both HTML and CSS.

let x = "Hello";             
let result = x + " World!";   
console.log(result);

How to use JS?

Using JS for your web or personal projects you can use script tag before the closing body tag or using script src to include external file that was linked into your html code.
Like a CSS JavaScript has also options to write code

let x = "Hello";             
let result = x + " World!";   
console.log(result);

JavaScript Printing/Output Methods

There are common Printing/Output method available in JS: document.write() used to print anything on screen/desktop alert() is used to show alerts on a page when it will be loaded. console.log() is a method which was commonly used by developers to see error or used as debugging methods. innerHTML or innerText is a method used to write something in on page.

let x = "Hello";             
let result = x + " World!";   
console.log(result);

JavaScript Input Methods

One of the most common method used for input is prompt that was show like a alert but use to input from user available in JS: prompt is a common method to input numbers, strings, symbols etc..... but if you want to input only numhers +prompt() or Number(prompt()) are used.

let x = "Hello";             
let result = x + " World!";   
console.log(result);

JavaScript Variables/Containers

There are three common variables used in javascript var is global scope javascript function that was used in js to redeclare or reassign value to variable let function scope variable that is used to declare assign or reassign a value. const is a type of containers, that is used to store data values, as var or let used to reassing value but const only for fixed values that cannot be changed

// Using var
var name = "John";
// Using let
let age = 25;
// Using const
const pi = 3.14;

Concatenation

The process of linking or combining two or more strings, numbers and variables is known as concatenation. You can add two variable, variable and string, string and numbers etc.. Mostly + is used for concatenation.

let x = "Hello";             
let result = ${x} + "World";   
console.log(result);

Literals

Literals are fixed values directly written into the code. They represent constant values that do not change.
` ` are the template Literals which are allows you to combine a one two or more strings, numbers, varaible etc.

let x = "Hello";             
let result = x + " World!";   
console.log(result);