What is JavaScript ?
JavaScript ek programming language hai jo mainly websites ko interactive banane ke liye use hoti hai.
Matlab,
jab aap kisi website pe click karte ho, form fill karte ho, ya animation dekhte ho, to uske peeche JavaScript ka kaam hota hai.
JavaScript se aap kisi bhi webpage ke elements ko dynamically change kar sakte ho,
jaise buttons ka color badalna, images ko hide/show karna, ya data ko update karna bina page ko reload kiye.
Ye language browser ke andar hi kaam karti hai,
matlab aapko koi extra software install karne ki zaroorat nahi hoti.
Agar aap website develop karna chahte ho, to JavaScript seekhna zaroori hai,
kyunki ye website ko zyada engaging aur user-friendly bana deta hai.
Agar aapse interviewer puche ki
What is javascript
( to aap ko bas itnahi answer dena hai ki )
JavaScript ek aisi programing language hai jo websites ko smart aur interactive banata hai !
ab dekh te hai java script ki history ke bare me…….
History of JavaScript
JavaScript ki history thodi interesting hai!
JavaScript ko 1995 mein Brendan Eich ne develop kiya tha.
Us waqt woh Netscape company mein kaam kar rahe the.
Unhone ek choti si language banayi thi jo websites ko zyada interactive aur dynamic bana sake.
1 ) Shuruat (1995):
Brendan Eich ne JavaScript ko originally Mocha naam diya tha, phir usse LiveScript ka naam diya gaya. But, Netscape ne usse JavaScript ka naam diya, kyunki unhone socha ki Java naam ki language (jo bohot popular thi) ko include karne se logo ka interest zyada hoga.
2 ) Early Growth (1996)
Jab JavaScript thoda popular ho gaya, to ECMA International ne iski standardization ki process start ki. Iska pehla version ECMAScript 1 1997 mein release hua, jo JavaScript ka official version bana.
3 ) Development & Features (2000s):
2000 ke aas-paas JavaScript ka development continue raha, aur naye features add kiye gaye jaise better support for objects, arrays, etc. Fir, AJAX (Asynchronous JavaScript and XML) ka use popular ho gaya, jiski wajah se JavaScript ka usage websites mein aur bhi badh gaya, especially dynamic data loading ke liye bina page reload ke.
4 ) Modern JavaScript (2015 & beyond):
2015 mein JavaScript ka ek major update aaya, jisko ES6 ya ECMAScript 6 ke naam se jaana gaya. Is version mein kaafi naye features aaye, jaise arrow functions, promises, aur let/const keywords. Ye update JavaScript ko aur powerful aur easy-to-write bana gaya.
Aaj ke time mein JavaScript har website aur app mein use hota hai,
aur ek highly powerful tool ban gaya hai web development ke liye.
JavaScript ne apni journey mein kai changes dekhe, aur ab ye ek complete programming language hai jo not only browsers mein, balki servers aur mobile apps mein bhi use hoti hai.
To, JavaScript ka history yeh dikhata hai ki kaise ek chhoti si idea ne web development ko transform kar diya
JavaScript Versions
JavaScript ke kai versions aaye hain, aur har version ne JavaScript ko better banaya hai.
Ye versions mostly ECMAScript (ya ES) ke naam se jaani jaati hain,
jo JavaScript ke official standard hain. Chalo, in versions ko simple tareeke se samajhte hain :
1 ) ECMAScript 1 (ES1) – 1997
Pehla version! Is version mein JavaScript ka basic framework set kiya gaya. Basic features jaise variables, functions, aur operators ko define kiya gaya.
2 ) ECMAScript 2 (ES2) – 1998
Is version mein mainly bug fixes kiye gaye aur kuch minor updates laaye gaye. Yeh version mostly improvement tha, major new features nahi the.
3 ) ECMAScript 3 (ES3) – 1999
Yeh version thoda zyada important tha! Ismein new features add kiye gaye jaise regular expressions (jo patterns ko match karne ka kaam aate hain), better error handling, aur arrays ke liye naye methods. Yeh version JavaScript ko aur powerful bana gaya.
4 ) ECMAScript 4 (ES4) – Never released
Is version ka plan bana tha, lekin kabhi release nahi ho saka. Bahut zyada changes aur improvements propose kiye gaye the, lekin language ki complexity badh gayi thi, isliye isse cancel kar diya gaya.
5 ) ECMAScript 5 (ES5) – 2009
Yeh ek kaafi important version tha! Ismein bohot saare naye features aaye, jaise strict mode (jo code ko zyada strict aur error-free banata hai), JSON support, aur Array methods (jaise forEach, map, etc.). Is version ne JavaScript ko modern web development ke liye ready bana diya.
6 ) ECMAScript 6 (ES6) / ES2015 – 2015
Yeh version JavaScript ka game-changer bana! Is version mein bohot saare naye features aaye:
let aur const keywords (jo variables ko zyada control karte hain)
Arrow functions (shorter syntax for functions)
Promises (asynchronous code ko handle karne ke liye)
Classes (jo object-oriented programming ko support karte hain)
Modules (code ko better organize karne ke liye)
ES6 ne JavaScript ko modern aur zyada efficient banaya.
7 ) ECMAScript 2016 (ES7) – 2016
Is version mein kuch chhote changes aaye, jaise:
Exponentiation operator (x**y, jo x raised to the power y hota hai)
Array.prototype.includes method, jo arrays mein kisi element ka presence check karne ka easy tareeka deta hai.
8 ) ECMAScript 2017 (ES8) – 2017
Is version mein kuch aur useful features aaye:
async/await (jo asynchronous code ko zyada readable aur easy-to-write banaata hai)
Object.entries() aur Object.values() (jo objects ke values aur entries ko handle karne mein madad karte hain)
9 ) ECMAScript 2018 (ES9) – 2018
Yeh version thoda specific tha aur kuch aur improvements laaye:
Asynchronous Iteration (asynchronous code ko iterate karne ka method)
Rest/Spread properties for objects (jo objects ko copy ya merge karna aur unka spread karna aasaan banaate hain)
10 ) ECMAScript 2019 (ES10) – 2019
Is version mein kuch aur helpful features aaye:
Array.prototype.flat() aur Array.prototype.flatMap() (jo arrays ko flatten aur transform karte hain)
Object.fromEntries() (jo arrays of key-value pairs ko object mein convert karte hain)
11 ) ECMAScript 2020 (ES11) – 2020
Yeh version thoda advanced tha:
Nullish coalescing operator (??) (jo null ya undefined ko check karta hai)
Optional chaining (?.) (jo objects ke properties ko safely access karne ka tareeka deta hai)
BigInt (jo bahut bade numbers ko handle karne ke liye use hota hai)
12 ) ECMAScript 2021 (ES12) – 2021
Is version mein:
Logical Assignment Operators (jaise &&=, ||=, ??=)
String.prototype.replaceAll() (jo string mein sabhi occurrences ko replace karta hai)
13 ) ECMAScript 2022 (ES13) – 2022
Recent updates mein:
Top-level await (jo asynchronous code ko modules mein directly use karne ki facility deta hai)
Private methods aur fields for classes (jo class ke andar ke properties ko private banate hain)
14 ) ECMAScript 2023 (ES14) – 2023
Is version mein kuch aur improvements aaye, jaise:
Array groupBy method (jo arrays ko categories mein group karne ka kaam karta hai)
Conclusion :
JavaScript ka har version apne time pe kuch na kuch naye features aur improvements lata hai. Aaj ke time mein JavaScript bohot powerful aur flexible language hai, jise web, mobile apps, aur servers ke liye use kiya jata hai. Har version ne JavaScript ko aur advanced aur developer-friendly banaya hai!
How to run JavaScript?
JavaScript ko run karna kaafi simple hai! Aap JavaScript ko do main tareekon se run kar sakte ho: Browser mein ya Node.js ke through. Chalo, dono tareekon ko samajhte hain:
1 ) Browser Mein JavaScript Run Karna :
Sabse simple tareeka hai apne browser ka use karna, jaise Chrome, Firefox, ya Edge.
Step-by-step process :
Step 1: Apne browser ko open karo (jaise Chrome ya Firefox).
Step 2: Developer Tools ko open karo :
Chrome: Ctrl + Shift + I (Windows) ya Cmd + Option + I (Mac)
Firefox: Ctrl + Shift + I (Windows) ya Cmd + Option + I (Mac)
Edge: Ctrl + Shift + I (Windows)
Step 3: Developer Tools mein, Console tab pe click karo.
Step 4: Ab yahan pe aap JavaScript code directly likh sakte ho.
Jaise:
console.log(“Hello, JavaScript!”);
Step 5: Enter press karo, aur aapko console mein output dikhega:
Hello, JavaScript!
2. HTML File Mein JavaScript Run Karna :
Agar aap ek website banate ho, to aap HTML file ke andar JavaScript likh ke run kar sakte ho.
Step-by-step process:
Step 1: Ek simple HTML file create karo, jaise index.html.
Step 2: Us HTML file mein <script> tag ke andar JavaScript code likho:
<!DOCTYPE html>
<html lang=”en”>
<head>
<meta charset=”UTF-8″>
<meta name=”viewport” content=”width=device-width, initial-scale=1.0″>
<title>My First JS</title>
</head>
<body>
<h1>Welcome to JavaScript!</h1>
<script>
console.log(“Hello, from JavaScript!”);
</script>
</body>
</html>
3 ) Node.js ke Through JavaScript Run Karna :
Agar aap JavaScript ko server-side pe run karna chahte ho,
to Node.js ka use kar sakte ho.
Isse aap JavaScript ko directly apne computer par run kar sakte ho bina browser ke.
Step-by-step process:
Step 1: Sabse pehle, Node.js apne system pe install karo. (Node.js ki website se download karo: nodejs.org)
Step 2: Ek new file banaye, jaise app.js.
Step 3: Us file mein apna JavaScript code likho :
console.log(“Hello from Node.js!”);
Step 4: Terminal ya Command Prompt open karo.
Step 5: Us directory mein jao jahan aapki app.js file hai.
Step 6: Command likho:
node app.js
Step 7: Aapko terminal mein output milega:
Hello from Node.js!
Conclusion :
Agar aap sirf thoda simple test karna chahte ho, to browser console sabse asaan tareeka hai.
Agar aap ek full-fledged website bana rahe ho, to HTML file mein JavaScript code likh kar use kar sakte ho.
Agar aap server-side JavaScript run karna chahte ho, to Node.js ka use karo.
Bas, itna hi! JavaScript run karne ka process kaafi simple hai aur aap in methods ka use kar ke apne code ko easily test kar sakte ho.
