JavaScript Programming Complete Notes | From Basics to DOM with Real Examples

🌐 JavaScript Programming – Beginner to Advanced (With Real-Time Examples)
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🔹 1. Introduction to JavaScript
JavaScript is a lightweight, interpreted scripting language used to make websites interactive and
dynamic. It runs directly in web browsers and powers everything from clickable buttons to full web
apps.


> Why JavaScript?




Runs in the browser (no need for installation)


Adds life to static HTML pages


Supports event handling, validation, and animations


Used in both frontend and backend (Node.js)




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🔹 2. JavaScript Basics
Syntax is case-sensitive


Statements end with ; (optional but preferred)


Runs inside <script> tag in HTML or in .js files




Variables:


let name = "Yuva";
const pi = 3.14;
var age = 20;


Data Types:


String, Number, Boolean, Object, Array, Null, Undefined

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🔹 3. Operators
Arithmetic: +, -, *, /, %


Comparison: ==, ===, !=, >, <


Logical: &&, ||, !


Assignment: =, +=, -=




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🔹 4. Conditional Statements
if (score >= 50) {
alert("Pass");
} else {
alert("Fail");
}




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🔹 5. Loops in JavaScript
For Loop:


for (let i = 0; i < 5; i++) {
console.log(i);
}


While Loop:


let i = 0;