Reference

📖 Glossary — Web Words Explained

Every strange word from the lessons, explained in normal-kid language.

The big three

Word	What it means
HTML	The language for the content and structure of a page — the walls of the house. (HyperText Markup Language)
CSS	The language for how a page looks — the paint. (Cascading Style Sheets)
JavaScript	The language that makes a page do things — the electricity. Not related to Java (confusing, we know).

HTML words

Word	What it means
Tag	A label in angle brackets. `<h1>` opens, `</h1>` (with the slash) closes.
Element	A complete brick: opening tag + content + closing tag. `<p>Hi!</p>` is one element.
Attribute	Extra info inside an opening tag: `<img src="cat.jpg" alt="a cat">`. Name = value, in quotes.
class	A group name you invent for bricks: `class="card"`. Many bricks can share one class. CSS finds them with `.card`.
id	A unique name for exactly ONE brick: `id="buy"`. CSS finds it with `#buy`, JavaScript with `getElementById("buy")`.
Skeleton	The frame every page needs: `<!DOCTYPE html>`, `<html>`, `<head>` (invisible info) and `<body>` (visible stuff).
Semantic tag	A box with a meaningful name — `<header>`, `<main>`, `<section>`, `<footer>` — so readers (and AIs) instantly know what it's for.
Nesting	Bricks inside bricks, like `<li>` items living inside a `<ul>` list. Inner bricks must close before outer ones.

CSS words

Word	What it means
Selector	The WHO of a CSS rule — which bricks get painted. `h1`, `.card`, `#buy`.
Property	The WHAT — which thing about them changes: `color`, `padding`, `font-size`.
Value	The choice: `purple`, `16px`, `center`.
Box model	The secret: every element is a box with layers — content, then padding (space inside), then border (the frame), then margin (space to other boxes).
Flexbox	A layout tool: put `display: flex` on a parent box and its children line up like train cars.

JavaScript words

Word	What it means
Script	A list of instructions for the browser to run, inside a `<script>` tag at the end of `<body>`.
Function	A recipe of steps with a name (or no name), waiting to be run — like a saved spell.
Event / listener	An event is something that happens (a click!). A listener (`addEventListener`) is a robot ear that waits for it and then runs your function.
Console	The browser's secret window where errors appear in red. Right-click → Inspect → Console. Engineers live here.
const	Makes a name for a thing so you can use it later: `const btn = ...`. Short for "constant".
Variable	A labeled memory box that holds a value. `const` = a box that never changes, `let` = a box you can refill.
String	Words in quotes: `"hello"`. Even `"5"` is words, not a number — quotes decide!
Number	A value with no quotes that math works on: `5 + 5` is `10`, but `"5" + 5` is `"55"` (gluing).
if / else	Code that chooses a path: `if (question) { do this } else { do that }`. Remember: `=` puts, `===` asks.
Parameter	The ingredient slot of a function: in `function cheer(name)`, `name` is the slot you fill when you call it.
return	How a function hands its answer back. No return = `undefined` (an empty box).
undefined	JavaScript's way of saying "this box is empty / doesn't exist". You'll meet it a thousand times. It's a clue, not a disaster.
Array	A train of boxes in one variable: `["fast", "cool", "cheap"]`. Counting starts at ZERO: `[0]` is the first one.
Loop	Code that repeats: `for (const f of features) { ... }` runs once for every item in the train.
innerHTML	Like `textContent`, but the words are read as HTML bricks — so `"<li>fast</li>"` becomes a real list item.

General words

Word	What it means
Browser	The app that reads HTML files and draws them — Chrome, Safari, Firefox.
File	A saved document. Web pages end in `.html`.
URL	An internet address, like `https://google.com`. In `href` or `src`, it can also just be a neighbor file's name.
Landing page	A one-page website whose whole job is to make one product look amazing. Anatomy: hero → features → footer.
Hero section	The big top part of a landing page: giant headline, one-sentence promise, and a button.
Vibe coding	Building software by telling an AI what you want. Works best when you can READ what the AI wrote — which is the whole point of this course.
Prompt	Your work order to the AI. A pro prompt says: WHAT to build, WHO it's for, the PARTS, the RULES, and the BEHAVIOR.
Iterate	Improving in small steps: ask for one small change, test it, then ask for the next. Beats "redo everything" every time.
Bug report	How pros ask for help: "I expected X. Instead Y happens. Here's the console error: [paste]. Here's my code: [paste]."
Code review	Reading code BEFORE accepting it — skimming the structure, checking the names, following one thread. Never paste in what you haven't skimmed.
classList	JavaScript's sticker tool: `el.classList.add("open")`, `.remove`, `.toggle` — put a class sticker on or take it off, so different CSS applies. All over AI code.