RBS CODE · QUICK REFERENCE

JavaScript Skills Map

One page. What you know, what JS3 adds, and what unlocks later.

JS3 is a game-skills map, not a giant lesson. You already know movement from JS2. JS3 adds the rules that turn movement into a game.

JS1 · THINK

JavaScript 1

Work with values and decisions.

<script> — start JavaScript

alert() — show a message

let — remember a value

"text" — strings

prompt() — ask a question

Number() — make a number

+ - * / — maths

if / else — choose what happens

== != < > <= >= — compare values

JS2 · CONTROL

JavaScript 2

Control real things on the page.

function — name instructions

onclick — run code on click

getElementById() — find an element

.value — read an input

.innerText — change text

.style — change CSS

.style.left / top — move an object

x / y — remember position

number + "px" — CSS position

JS3 · GAME RULES

JavaScript 3

Turn movement into a real game.

parameters — give a function information

return — get an answer back

keydown / event.key — keyboard controls

getBoundingClientRect() — object edges

&& — BOTH rules must be true

|| — EITHER rule can be true

!= and ! — not equal / NOT

collision — are two objects touching?

boundaries — stay inside the game

score / health / gold — change numbers

Math.random() — random positions

console.log() — see what is happening

UNLOCK LATER

Only when a project needs it

Timers
setInterval()
automatic movement

Arrays
[]
inventory, walls, bullets

Loops
for
check many objects

Smooth controls
keydown + keyup
hold keys down

Platformer movement
ySpeed + gravity
jump and land

Create objects
createElement()
bullets / new enemies

Objects
{ }
bundle game data

Save progress
localStorage
keep data

Memory trick: JS1 thinks → JS2 controls the page → JS3 adds game rules.