JavaScript Syntax & Rules Kya Hote Hain

JavaScript ek powerful aur dynamic programming language hai jo web development ke liye use hoti hai. Iska proper syntax aur rules samajhna bahut zaroori hai taaki aap error-free aur efficient code likh sakein. Yahaan hum JavaScript ke basic syntax aur essential rules ko detail mein samjhenge, jo beginners ke liye kaafi helpful honge.

1. JavaScript Syntax Kya Hai?

Syntax ka matlab hai JavaScript likhne ka proper format ya structure. Har programming language ka ek predefined syntax hota hai jo batata hai ki code likhne ka sahi tareeka kya hai. Agar syntax sahi nahi hoga, toh JavaScript errors show karega aur code execute nahi hoga.


console.log("Hello, World!");

Explanation:

console.log() ek predefined method hai jo console pe output show karne ke liye use hota hai.
"Hello, World!" ek string hai jo console pe print hogi.
Statement ke end me ; (semicolon) lagana optional hota hai, par readability ke liye recommended hai.

2. JavaScript Statements

JavaScript code ek ya ek se zyada statements ka combination hota hai. Har statement ek specific task perform karta hai, jaise ki kisi variable ko define karna, kisi value ko print karna, ya kisi function ko call karna.

Important Points about Statements:

JavaScript statements generally ek line me likhe jaate hain.
Multiple statements ko ek saath likhne ke liye ; (semicolon) ka use kiya jata hai, lekin yeh optional hai.
JavaScript automatically line breaks ko detect kar leta hai, lekin kabhi-kabhi ambiguous cases me errors aa sakti hain, isliye semicolon lagana best practice hai.


let x = 10;  // Variable x ko value assign ki gayi
let y = 20;  // Variable y ko value assign ki gayi
let sum = x + y;  // Dono values ka sum store kiya gaya
console.log(sum);  // Output: 30

Explanation:

Pehle do statements x aur y variables define kar rahe hain.
Teesra statement sum variable me x aur y ka addition store kar raha hai.
Last statement console.log(sum); output ko console pe print karega.

3. JavaScript Comments

Comments ka use code ko explain karne ke liye kiya jata hai. Yeh execution ka part nahi hote, sirf readability aur documentation ke liye helpful hote hain. JavaScript me do types ke comments hote hain:

(i) Single-line Comment:

Agar aap ek hi line me comment likhna chahte hain, toh // ka use karte hain.


// Yeh ek single-line comment hai
console.log("Hello, JavaScript!");  // Yeh bhi ek comment hai

Explanation:

// ke baad likha gaya text comment hota hai, jo sirf explanation ke liye hota hai aur JavaScript engine usko ignore karta hai.

(ii) Multi-line Comment:

Agar aap multiple lines ka comment likhna chahte hain, toh /* ... */ ka use kar sakte hain.


/*
Yeh ek multi-line comment hai
Jo multiple lines cover karta hai.
*/
console.log("Hello, JavaScript!");

Explanation:

/* se comment start hota hai aur */ se end hota hai.
Yeh method tab useful hota hai jab aap kisi bade code block ko temporarily disable ya explain karna chahte hain.

JavaScript ka syntax aur rules simple aur easy-to-understand hain, bas inko sahi tarike se follow karna zaroori hai. Statements, comments aur syntax ko theek se samajhna ek beginner ke liye JavaScript sikhne ka first step hai.

Agar aap error-free aur clean code likhna chahte hain, toh:

Proper indentation aur spacing ka dhyan dein.
console.log() ka use karke debugging karein.
Comments likhkar apne code ko readable aur understandable banayein.

Yeh basic rules follow karne se aap ek better JavaScript developer ban sakte hain!

Quiz: Test Your Knowledge on JavaScript Syntax & Rules

Bonus: Practical Application!

Aaj hi apne webpage par JavaScript Syntax & Rules ka istemal karke dekhein!

JavaScript ko sahi tareeke se samajhne ke liye different concepts jaise variables, functions, loops, events, scope, aur operators ka upayog karein aur apne webpage ke functionality ko aur bhi interactive banayein.