Conditional Statements (if, else if, else)

Har program ko eventually value ke hisaab se alag alag cheezein karni padti hain. JavaScript iske liye if, else if, aur else use karta hai — curly braces se har block mark hota hai, Python ki indentation ke ulat.

let age = 20;
if (age >= 18) {
  console.log("You are an adult");
} else {
  console.log("You are a minor");
}

You are an adult

=== vs. ==

JavaScript mein do equality operators hain, aur inka farq genuinely matter karta hai: === value aur type dono ek saath check karta hai (strict equality), jabki == compare karne se pehle types convert kar deta hai (loose equality), jo surprising results de sakta hai.

console.log(5 === 5);
console.log(5 === "5");
console.log(5 == "5");

true
false
true

Hamesha === use karo jab tak koi specific reason na ho. == chup chaap "5" aur 5 ko equal bana deta hai, jo shayad hi kabhi aap actually chahte ho, aur subtle bugs ka common source hai.

else if se conditions ko chain karna

let score = 75;
if (score >= 90) {
  console.log("A");
} else if (score >= 80) {
  console.log("B");
} else if (score >= 70) {
  console.log("C");
} else {
  console.log("F");
}

C

JavaScript har condition ko upar se neeche check karta hai aur jo pehli condition true milti hai wahin ruk jaata hai — score >= 70 else tak pahunchne se pehle hi match ho jaata hai, isliye "C" print hota hai aur uske baad sab skip ho jaata hai.

Aage: for loops — collection ke har item par code ko repeat karna.