JavaScript

Chapter 3 — JS Conditionals & Loops

📚 Chapter Overview

JavaScript logic allows your website to react to different scenarios. In this chapter, you will learn how to use if-else statements for decision-making and for loops to handle repetitive data.

Learning Objectives:

3.1 If-Else Decisions

Part 1 — Definition

Conditional statements check a condition. If it is true, the code inside the block executes. If false, it moves to the else block. You can chain multiple checks using else if.

Part 2 — Syntax

if (condition) {
    // True code
} else if (anotherCondition) {
    // Alternative code
} else {
    // Default code
}

Part 3 — Example

Problem: Check if a user is old enough to enter a site.

script.js 
let age = 17;
if (age >= 18) {
    console.log("Access Granted");
} else {
    console.log("Access Denied");
}

Part 4 — Video

Video: Coming Soon

3.2 Repetition with For Loops

Part 1 — Definition

A for loop allows you to run a block of code multiple times. It is commonly used to process items in a list (Array) or to repeat a mathematical calculation.

Part 2 — Syntax

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

Part 3 — Example

Problem: Print each student's name from a list.

script.js 
let students = ["Ali", "Sara", "John"];
for (let i = 0; i < students.length; i++) {
    console.log(`Student ${i+1}: ${students[i]}`);
}

Part 4 — Video

Video: Coming Soon

🏆 Chapter Challenge

Challenge Objective

Create a "FizzBuzz" program that uses both logic and loops.

Requirements

Step-by-Step Process

  1. Use a for loop from 1 to 20.
  2. Use the modulus operator % to check for divisibility.
  3. Use an if-else if-else ladder.

Expected Deliverables

Solve in Editor