JavaScript

JavaScript is a high-level, interpreted programming language primarily used to create interactive and dynamic content on websites. It is one of the core technologies of the web, along with HTML (for structure) and CSS (for styling).

Internal = script is inside HTML file.

External = script is in separate .js file and linked.

Inline = script is inside element attribute.

Primitive Data Types :

String => Text data
Number => Numeric values (integers, decimals)
Boolean => True or false
undefined => A variable declared but not assigned
null => Represents intentional "no value"
BigInt => Large integers
Symbol => Unique and immutable identifier

Reference (Non-Primitive) Data Types :

Object => Collection of key-value pairs
Array => Ordered list of value
Function => Block of reusable code
Date => Built-in object types

Variable Declarations:

var => Can be redeclared and reassigned
let => Can be reassigned, but not redeclared in the same scope
const => Cannot be reassigned or redeclared