? JavaScript if...else Statement

The if...else statement in JavaScript is used to execute different blocks of code based on a condition.

? Syntax

if (condition) {  // code to run if condition is true} else {  // code to run if condition is false}

? Example

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

? if...else if...else Chain

You can check multiple conditions:

let score = 85;if (score >= 90) {  console.log("Grade: A");} else if (score >= 80) {  console.log("Grade: B");} else if (score >= 70) {  console.log("Grade: C");} else {  console.log("Grade: F");}

? Ternary Operator (Shorthand)

let isLoggedIn = true;let message = isLoggedIn ? "Welcome!" : "Please log in.";console.log(message);

? Tips

• Use === instead of == for strict comparison.

• Use {} even for one-line blocks (for readability and safety).

• Be careful with falsy values like 0, "", null, undefined, false, and NaN.

Would you like examples of if...else with DOM, user input, or form validation?