# What the quiz preview means by a browser copy

Draft • Research checked 4 October 2026 • AI-assisted DomDNA editorial content. No independent clinical review or publication is claimed. General education, not individual medical advice.

You return to a quiz and see your earlier answers. That can feel like an account has remembered you. In the checked DomDNA preview, the resume feature instead uses a copy in the current browser, subject to a time limit and storage availability.

This article describes commit 015c7c1926731bfadfa6ede67d0e0b9f401f9674, principally src/utils/quizSession.ts and src/pages/Quiz.tsx. It is source-based preview documentation, not a live deployment check or a guarantee across browsers and devices.

## The clock starts when the session starts

The preview's stored session has a start timestamp. Its intended lifetime is up to twenty-four hours after that start, not twenty-four hours after each return visit.

Here is a hypothetical example. You start at ten in the morning and return at nine the following morning. Returning does not reset the original clock and promise another full day. At or beyond the expiry boundary, the stored copy is not accepted as a resumable session by the checked decoder.

The implementation also checks the stored structure and answer options. Old, malformed or invalid data can be rejected. A browser value is not trusted merely because it exists.

That validation matters when a quiz changes. A saved answer from an older question set may no longer match a current option. The safe response is not to invent a replacement answer that makes the old record look complete.

## Browser storage is not a cross-device account

The [MDN Web Storage explanation](https://developer.mozilla.org/en-US/docs/Web/API/Web_Storage_API) describes storage tied to a browser context and origin. It provides the underlying mechanism, not a promise that this application can recover data from another device.

The preview does not make this local copy a synchronised account. Opening the same route in another browser or device should not be treated as a way to retrieve the earlier local answers.

If you save a quiz to the service, that is a separate operation. The local resume mechanism still should not be described as an account-recovery feature or proof that a server record is current.

For a hypothetical handover, someone who changes from a phone to a laptop may need to start again. The fact that both screens show the same website name does not mean they share the same browser storage.

## Storage can disappear before the limit

The [MDN storage-limit documentation](https://developer.mozilla.org/en-US/docs/Web/API/Storage_API/Storage_quotas_and_eviction_criteria) explains that storage behaviour has limits and browser-specific details. Users can also clear site data, and settings can prevent storage from working as expected.

The [Mozilla private-browsing explanation](https://www.mozilla.org/en-US/firefox/browsers/incognito-browser/) provides context for local data being removed when a private session ends. Private mode is therefore not a way to guarantee a resume copy.

In the checked preview, a storage failure produces a notice rather than a claim that persistence succeeded. The intended twenty-four-hour boundary is a maximum acceptance window for this implementation, not a minimum survival guarantee.

Do not leave important health information only in a temporary browser record. The quiz is a learning tool, not a medical-record system.

## A restored receipt is a historical receipt

The preview warns that restored saving and email details show the last response received and have not been checked again. That is a useful distinction between stored information and a new service confirmation.

If the screen restores a previous save status, it does not prove that an email is currently in your inbox. If the earlier result was local only, restoration does not retroactively save it to the service.

The restored summary is recomputed by the checked code from valid answers. It is not a signed clinical report preserved unchanged across every future release.

## Clearing one copy has a limited meaning

The “Retake quiz” action removes the local quiz copy from that browser in the checked implementation. It does not, by itself, delete a quiz previously saved to the service.

A request concerning stored service data needs the appropriate privacy contact or service process. Clearing browser data and requesting deletion of a server record are different actions.

## What you can do with this

Before relying on resume, read the storage notice and remember the original start time. On a shared device, use the available local-clearing control when you are finished.

[The public quiz route](https://domdna.com/quiz) does not confirm deployment of this preview. Check the release you are actually using; browser behaviour and service records have separate boundaries.