JavaScript Learning Repository

A personal collection of lessons, notes, exercises, and small experiments created while studying JavaScript with the Curso em Vídeo JavaScript course.

This repository records a learning journey rather than a single finished application. It keeps early examples alongside more interactive browser exercises so that beginners can follow the progression from basic input and output to DOM manipulation, arrays, functions, and objects.

Work in progress: the repository is being reorganized and refactored gradually. Some files have already received clearer English comments and identifiers, while others still contain Portuguese text, older naming conventions, duplicated material, or intentionally simple implementations.

What is covered

JavaScript fundamentals

• Variables declared with let and const, primitive values, and typeof
• Arithmetic, comparison, logical, assignment, and ternary operators
• Type conversion with Number(), Number.parseFloat(), and string conversion
• Template literals and string properties/methods such as length, toUpperCase(), slice(), trim(), and replace()
• Number formatting with toFixed() and toLocaleString()
• Input and output through browser dialogs, the document, forms, and the console
• Simple, compound, and nested conditionals, plus switch
• while, do...while, for, and for...in loops

Functions and data structures

• Function declarations, parameters, return values, and default parameters
• Function expressions, arrow functions, and recursive functions
• Arrays: indexing, length, push(), sort(), indexOf(), filter(), and iteration
• Validation, duplicate detection, accumulation, minimum/maximum values, totals, and averages
• Object literals, properties, methods, and this

Browser and web programming

• DOM selection with getElementById(), getElementsByTagName(), getElementsByName(), and querySelector()
• Reading form values and updating content with innerText and innerHTML
• Dynamic styling through the style API
• Creating and inserting elements with createElement(), setAttribute(), and appendChild()
• Inline event handlers and addEventListener() for click and mouse events
• Page-load behavior with onload
• The Date API for the current hour, year, and day of the week
• HTML forms, semantic page sections, inline/external CSS, Flexbox, and responsive viewport metadata
• Dynamic image and color changes using local WebP assets

Repository structure

The directory names mostly follow the original course organization. aula means “lesson,” and the abbreviated exrc directories contain exercises.

Path	Content
CursoJS/aula04/	First HTML/JavaScript page and browser dialog methods
CursoJS/aula06/	Variables, prompts, conversion, strings, arithmetic, and number formatting
CursoJS/aula09/	DOM selection, content changes, document properties, and dynamic styles
CursoJS/aula10/	DOM events and a form-based addition exercise
CursoJS/aula11/	Simple and compound conditionals in console and browser examples
CursoJS/aula12/	Nested conditions, Date, and switch
CursoJS/aula13_aula14/	while, do...while, and for loops
CursoJS/aula15/	Arrays, iteration, searching, mixed values, and filter()
CursoJS/aula16/	Functions, default parameters, arrow functions, and factorial recursion
CursoJS/aula17/	A basic object with properties, a method, and this
CursoJS/exrc/	A reusable page template plus the time-of-day and age-checker exercises
CursoJS/exrcE/	Counter and multiplication-table exercises
CursoJS/exrcF/	Number analyzer and an unfinished exercise template
exrc/	A second copy of the template, time-of-day, and age-checker material also stored under CursoJS/exrc/

The repository also includes an MIT LICENSE and the local images used by the time-of-day and age-checker pages.

Browser exercise examples

Exercise	What it demonstrates
Time of Day	Reads the current hour and changes the message, background, and image
Age Checker	Validates a birth year, calculates age, reads radio controls, and creates an image element
Counter	Validates start/end/step fields and produces ascending or descending sequences
Multiplication Table	Builds <option> elements dynamically inside a <select>
Number Analyzer	Stores unique numbers and reports count, minimum, maximum, sum, and average

The generic modelo pages are scaffolds, and CursoJS/exrcF/modeloEx19/script.js is currently empty.

Running the examples

There are no package dependencies, build tools, or installation steps. A modern browser is enough for the HTML exercises; Node.js is optional for the console-only scripts.

Browser exercises

You can open any .html file directly in a browser. For a local HTTP server, run this command from the repository root:

python3 -m http.server 8000

Then visit a file through http://localhost:8000, for example:

http://localhost:8000/CursoJS/aula10/ex006/ex006.html
http://localhost:8000/CursoJS/exrc/modeloEx14/model.html

Some early lessons display prompts, alerts, or confirmation dialogs immediately when the page loads. Keep each HTML file beside its associated script, stylesheet, and images so its relative paths continue to work.

Console exercises

Run the standalone lesson scripts with Node.js, for example:

node CursoJS/aula11/ex008_ex009.js
node CursoJS/aula15/ambiente.js
node CursoJS/aula16/funcao01_funcao02_funcao03_funcao04_funcao05.js
node CursoJS/aula17/objeto01.js

Scripts inside the browser exercise directories depend on the DOM and should be run through their corresponding HTML pages instead of directly with Node.js.

Current status

Refactoring is ongoing. The current work includes translating comments and visible text from Portuguese to English, replacing short or ambiguous identifiers with clearer names, and improving organization and readability. Progress is uneven by design: newer revisions coexist with original course-era material so the repository still shows the learning process.

At present:

• English and Portuguese are both present in interfaces, comments, identifiers, and filenames.
• Some early lesson files are more heavily revised than the later browser exercises.
• The top-level exrc/ directory largely duplicates material in CursoJS/exrc/.
• Generic templates and the exercise 19 script remain incomplete placeholders.
• There is no automated test suite; examples are intended to be explored in a browser or run individually with Node.js where appropriate.

This is intentionally an educational, beginner-friendly code collection—not a production application. Older patterns and inconsistencies may remain until the relevant lesson or exercise is revisited.

License

This repository is available under the MIT License.