JavaScript Basics

Every piece of information in JavaScript has a "type" - just like in real life where we have different types of things: numbers, words, yes/no answers, etc.

Here are the main types of data in JavaScript:

• •Number - Any number, whole or decimal

Examples: 42, 3.14, -10, 0
Use for: age, price, score, temperature

• •String - Text wrapped in quotes (single or double)

Examples: "Hello", 'JavaScript', "123" (yes, numbers in quotes are text!)
Use for: names, messages, addresses, any text

• •
  Boolean - Only two possible values:true or false

Examples: true, false
Use for: yes/no questions, on/off switches, completed/not completed

• •Undefined - A variable that exists but has no value yet

Example: let myVariable; (declared but not assigned)

• •Null - Explicitly saying "this has no value"

Example: let data = null; (intentionally empty)

Why do types matter? JavaScript needs to know what type of data you're working with so it can handle it correctly. You can't do math with words, and you can't capitalize a number!