EnQuiz
An offline-first, bilingual revision app for Entrepreneurship.
A 300-question bank across five chapters of an undergraduate Entrepreneurship
course, delivered as timed mock exams and chapter practice with immediate
explanations — plus automatic tracking of every missed question, a per-chapter
diagnosis of each paper, and an importer that matches a pasted question paper to
a pasted answer key by question number. It runs entirely in the browser, installs
to the home screen, and keeps working with no network connection.
▶️ Live app: https://thuyhuongctu.github.io/EnQuiz/
📦 Archived on Zenodo: 10.5281/zenodo.21850735
| | | | |
|---|
| 300 questions | 5 chapters | 2 languages | 0 servers | ~6,700 lines, no framework |
Contents
Design position
Three commitments distinguish EnQuiz from a general-purpose quiz platform, and
each one is a constraint the code is held to:
- Learning data stays on the device. There is no account and no learning
database. Every result, every missed question and every imported set lives in
the learner's own browser — which is what makes the privacy claim below
verifiable by reading the source rather than trusting an operator. The app
makes two external requests, both described under Privacy: an
anonymous, cookieless visit counter, and, only when a learner unlocks the case
study materials, a record of the school email entered.
- No build step. The published site is the repository. There is no bundler,
no transpiler and no dependency tree, so the archived Zenodo snapshot is
directly readable and directly runnable a decade from now.
- Offline-first, and honest about weight. The application shell is
pre-cached on first visit; the media is not. The song, the tour narration and
the introduction video are fetched only when a learner presses play, so
opening the app on a mobile data plan costs a few hundred kilobytes rather
than several megabytes.
Question bank
| Chapter | Topic | Questions |
|---|
| 1 | Overview of starting a business | 60 |
| 2 | Assessing opportunities and developing a business plan | 60 |
| 3 | Raising capital and key financial indicators | 60 |
| 4 | Choosing a business model | 60 |
| 5 | Marketing for a new business | 60 |
| Total | 300 |
The interface is bilingual English–Vietnamese; the question content stays in
Vietnamese, as taught in the course. A separate "KT330H" track adds instructor
case studies and a comprehensive review set — see
Extending the source.
Functionality
Practice modes
- Mock exam — a random paper with adjustable question count and time limit,
a live countdown, automatic submission when time runs out, scored out of 10.
- Practice by chapter — pick a scope; the correct answer and the
explanation appear immediately after each choice.
- Missed questions — every question answered wrongly is remembered;
answering it correctly later removes it from the list.
- Flagged questions — mark anything to return to.
- Merge questions & answer key — paste a paper into one box and an answer
key into the other; they are matched by printed question number, not paste
order.
- Answer review — question by question, with a per-chapter breakdown.
During a paper
- A counter bar in the header shows attempts, best score, and how many
questions remain unanswered correctly.
- A question grid for jumping around the paper, keyboard shortcuts
A/B/C/D
and ←/→, and a progress bar.
- On submission, an advice card names the chapter costing the most marks
and offers a one-tap button to practise exactly that chapter.
- Exam integrity nudges (mock exam only): a tab-switch warning, clipboard
disabled during the paper, and best-effort full-screen — a reminder, not a
lock, and nothing leaves the device.
Home screen
- A short introduction video, behind a cover image and a play button.
- The chapter list with per-chapter progress and mastery, each chapter
carrying an icon drawn for its subject.
- Attempt history, clearable at any time.
- Milestones: first attempt, a seven-day streak, a perfect 10, fifty attempts.
- Two clocks, Vietnam and France, each with its flag and UTC offset, and the
gap between them — computed from named time zones, so both the offsets and
the gap stay correct across daylight saving.
- The author's music in two versions — La lampe brûle encore with vocals,
and an instrumental intended to sit quietly under revision. Both loop.
Appearance
Four settings in Settings → Appearance: Follow device, Light, Clay
noir and Cosmic dark.
Clay noir is the application's dark look: a dark stone ground whose panels
appear moulded by hand, lit in gold. Its depth is made entirely of layered CSS
shadow, so it adds no image files and nothing to download; every
text–background pair on it was measured against WCAG AA, the lowest coming out
at 6.05:1. Cosmic dark is the dark look of earlier releases, kept for anyone
who preferred it.
Under Follow device — the setting until the learner chooses otherwise — a
phone set to light gives the light theme and a phone set to dark gives Clay
noir, and it switches live when the phone does. The choice is stored per
browser.
Guided tour
Ten steps, each highlighting the region of the screen it describes, opening
with a French greeting — « Bonjour ! Je m'appelle Hương. » The narration is
recorded audio in the author's own voice, 24 files across Vietnamese and
English, not machine speech; the text is always on screen, so the tour works
with the sound off. Audio is fetched only when the tour runs.
The complete narration script, in both languages, with the screen target, the
character pose and the audio file for every step, is published in
docs/LOI_THOAI_HUONG_AI.md.
Architecture
index.html every screen, and the inline SVG icon sprite
└── assets/js/
i18n.js bilingual dictionary and translation engine
storage.js progress, history, streak, imported sets (localStorage)
bank.js loads, normalises and merges the question bank
parser.js extracts questions and answers from pasted text
app.js practice modes, scoring, statistics, clocks, media
tour.js the guided tour and its recorded audio
└── data/manifest.js → data/ch01.js … ch05.js (60 questions each)
└── sw.js service worker: versioned offline copy of the shell
About 6,700 lines of HTML, CSS and JavaScript. No framework, no build step, no
package manager, no runtime dependency. Fonts are self-hosted rather than
called from a font CDN, so typography survives an offline launch.
Running it
Quickest: download the source and open index.html in a browser.
With a local server — required for the service worker and offline mode:
python3 -m http.server 8000
# then open http://localhost:8000
Publication: every push to main triggers .github/workflows/pages.yml,
which publishes https://thuyhuongctu.github.io/EnQuiz/. No manual step.
Installation: open the page in Chrome, Edge or Safari and choose Install
app / Add to Home Screen. A ⬇️ button also appears in the header when the
browser offers installation.
Offline behaviour
The service worker keeps a copy of the application under a versioned cache
(CACHE_VERSION in sw.js). Pages and code are fetched network-first, so a
new release appears immediately and falls back to the cache when the network
is gone; images and audio are served cache-first.
Large media is deliberately excluded from the pre-cache. The introduction
video goes further still: its <video> element carries no src at all
until the play button is pressed, and the service worker skips
assets/video/ entirely — a 24 MB file would consume most of the storage a
web application is permitted, and a media player requests byte ranges to
seek, which a cache can only answer with the whole file.
Privacy
Learning data never leaves the device. There is no account. Results,
missed questions, flags and imported sets stay in the learner's own browser;
Erase all data in Settings clears everything. No answer, score or progress
figure is transmitted anywhere.
Case study unlock records a school email. Opening the original case study
materials asks for a school email once per device. The email, the case ID and
the time are sent over HTTPS to a Supabase function so the instructors know
who viewed the materials. They are not shared, are kept for at most 12
months, and are deleted on request ([email protected], subject "Delete
EnQuiz data").
Visits are counted, anonymously. The app loads
GoatCounter, a cookieless analytics script
that stores no IP address, sets no identifier and does not follow visitors
across sites. It reports how many times the app was opened, on which day, and
from which country — nothing that identifies a person, and nothing about what
a learner answered. This is disclosed in the app's own Privacy panel, in
both languages, and in the full bilingual policy published at
chinh-sach.html,
which is also the policy linked from the Google Play listing.
Apart from the case study unlock above, the counter is the only external
request the app makes. It is served from a different origin, so the service
worker does not touch it; with no network it fails silently and the app
carries on.
Merge questions & answer key
Used to add or replace question sets without touching the source. Open
Merge questions & answer key from the home screen, paste into the two
boxes, then press Analyse to preview before saving.
Questions are matched to answers by the question number printed in the
paper, not by paste order, so any subset can be pasted — for example only
questions 31–60.
| Element | Accepted forms |
|---|
| Question numbering | Question 1: · Câu 1. · 1. · 1) |
| Options | A. · A) · (A) · a. — same line or separate lines, 2 to 6 options |
| Answer inside the paper | * before the correct option, or Answer: B / Đáp án: B at the end |
| Answer key | 1. B · Question 1: B · 1 - B · 1B · 1. B. followed by the answer text |
| Explanation (optional) | Explanation: … at the end of a question |
Imported sets are saved in localStorage and reloaded next time; each can be
deleted individually from the same screen.
Extending the source
A permanent question set. Create a file in data/, for example ch06.js:
registerBank({
id: 'ch06',
title: 'Chương 6 – Tên chương',
titleEn: 'Chapter 6 – Chapter name', // optional, used by the English interface
order: 6,
questions: [
{
q: 'Question text?',
a: ['Option A', 'Option B', 'Option C', 'Option D'],
c: 1, // zero-based index of the correct option
e: 'Explanation (optional)'
}
]
});
Add the file name to the array in data/manifest.js, add its path to the
SHELL list in sw.js, and bump CACHE_VERSION. The application loads and
merges it automatically, dropping questions whose text duplicates an existing
one. The c field also accepts "B", "2", or the exact text of the
correct option.
An interface language. Every display string lives in
assets/js/i18n.js, grouped by key; add a language by appending a block to
DICT with the same keys as the vi block. In HTML, static elements are
translated through data-i18n="key" (or data-i18n-html when the string
contains markup, and data-i18n-attr="title:key" for attributes). In
JavaScript, use t('key', { name: value }).
Media and artwork
Two characters, kept apart on purpose: Ms. Huong in an ao dai carries the
course, and Huong AI in the knit vest runs the guided tour.
| File | Where it appears |
|---|
huong-welcome.webp | home header, and results at the pass mark |
huong-quiz.webp | opens the chapter list, sits beside the question card, and appears on results below the pass mark |
huong-cheer.webp | results, score 8 and above |
video-poster.webp | the video cover — a real frame from the video itself |
class-group.webp | the banner on the exam setup screen |
vest-*.webp | Huong AI in the tour panel, one file per pose |
vest-avatar.webp | tour button, tour panel, advice card |
logo.svg · globe.svg · mekong-map.webp | mark, and faded backgrounds |
The Ms. Huong pictures on the home screen, the chapter list, the answering
screen and the video cover are whole frames from the introduction video,
used uncropped. Cut-outs were tried and abandoned: the transparency had hard
edges and a dark residue along the outline, measured at 40–42% of the edge
pixels, which showed as a jagged fringe around the hair and the dress. The
app icon is the exception — it comes from a cut-out whose outline
measured 3.5% dark, clean enough to sit on the icon's own ground.
To change a picture, replace the file and keep the name. Which picture
appears on the result screen is decided in renderResult() in
assets/js/app.js; the tour poses are in POSE_SRC in assets/js/tour.js.
Citation
If you use EnQuiz, please cite it. GitHub renders a Cite this repository
button from CITATION.cff.
Do, T. H., & Phan, A. T. (2026). EnQuiz: an offline-first bilingual quiz
app for entrepreneurship revision (Version v.1.2) [Computer software].
Can Tho University. https://doi.org/10.5281/zenodo.21850735
@software{do_phan_enquiz_2026,
author = {Do, Thuy Huong and Phan, Anh Tu},
title = {{EnQuiz: an offline-first bilingual quiz app for
entrepreneurship revision}},
version = {v.1.2},
year = {2026},
publisher = {Zenodo},
doi = {10.5281/zenodo.21850735},
url = {https://doi.org/10.5281/zenodo.21850735}
}
Zenodo mints two kinds of identifier: the concept DOI
10.5281/zenodo.21850735 always resolves to the latest release, while each
release also receives its own version DOI that pins an exact build. Cite
the concept DOI for the software in general and the version DOI for a
reproducible reference. Machine-readable metadata is in CITATION.cff and
.zenodo.json.
Authorship and ownership
Authors
Copyright subsists automatically under the Intellectual Property Law of Viet
Nam and the Berne Convention from the moment of creation; a Copyright Office
of Viet Nam registration is in preparation.
Scope of authorship. All 300 questions were written by Do Thuy Huong for
the course she teaches; they are not drawn from a departmental question pool.
The interface text, the character artwork, the recorded narration, the
introduction video and both songs are likewise her own work. Phan Anh Tu
contributed the KT330H case studies and comprehensive review content, and as
academic supervisor and co-author.
Institutional position. The first author is a lecturer at the Faculty of
Business and Law, Vinh Long University of Technology and Engineering, and a
PhD candidate at Can Tho University; the second author is at the School of
Economics, Can Tho University. The work was created outside any assigned
task, research project or funded programme of either institution and
without using their funds or facilities. Because a Can Tho University staff
member is named as co-author, the university's intellectual-property
regulations are being checked before the registration is filed.
Licence
EnQuiz is proprietary software. © 2026 Do Thuy Huong and Phan Anh Tu. All
rights reserved. It is not open source and it is not under a Creative
Commons licence. The full terms, in English and Vietnamese, are in
LICENSE.
Permitted, free of charge and without asking: using the app for your own
study and exam revision; sharing the link; installing it on your own
devices; importing your own question sets for use on your own device.
Requires written permission: copying, extracting or redistributing the
question content in any form; re-publishing the app elsewhere, even with
attribution; commercial use or use in paid teaching or training;
modification, translation or derivative works; removal of copyright notices.
Copying and the right-click menu are disabled in the app as a reminder. That
is a reminder, not a technical barrier — unauthorised copying is an
infringement however it is carried out.
For any other use, write to [email protected] for written permission.
