P3.1: JavaScript Basics & Variables

JavaScript is the programming language of the web. It controls the interactive behavior of websites.

1. Declaring Variables

Modern JavaScript uses let and const to store variables:

• const (Constant): Sourced for variables that should never change.
• let: Sourced for variables that will be reassigned.
• Never use var: It has outdated scoping behaviors.

Kyle SimpsonView Profile 🔗

Real-World Developer Case Study

15 Years Exp

RoleAuthor of You Don't Know JS

Salary₹85 Lakhs/yr equivalent

CompanyGetify Solutions

Core Tech Stack

JavaScript CoreScopesClosuresAsync JS

“Don't just write code; know how the compiler works. Const signifies that the variable reference will never be reassigned. Use it by default, and change to let only when required.”

2. Core Data Types

• String: "Hello"
• Number: 42, 3.14
• Boolean: true / false
• Null: Represents an intentional empty value.
• Undefined: Variable declared but not assigned.

🎓 Practice Assignment

1. Open your browser console.
2. Create variables representing your name (const), age (let), and student status (const).
3. Log them to the console.