# Test and develop

> Test mode outside RPG Desk, development mode inside the room and page errors.

Page: https://docs.rpgdesk.com/en/fichas/desenvolvimento/

Three tools help you make and fix a sheet: **test mode**, to test without RPG Desk; **development mode**, to test inside the room without reinstalling after each change; and **page errors**, to find what broke.

## Test mode

Open the sheet’s file straight in the browser (double-click it, or drag it onto a tab). Without RPG Desk around it, rpgdesk.js enters test mode:

*Screenshot:* The sheet in test mode: the fields filled in and the band with the Sheet owner role, the log open with two rolls and the Clear data button.

- everything works: fields, lists, tabs, math and rolls (rolled in the browser);

- the data is kept in the browser, and comes back when you reload the page;

- the band in the corner has:

  - **Role**: **GM**, **Sheet owner** or **Another player**. Switch to see what each one sees and can change;
  - **Log**: rolls, chat messages, notices, card bars, (pretend) webhooks and errors. The orange number counts the errors and the refused writes;
  - **Clear data**: starts the sheet from scratch.

The band speaks the browser’s language. The live sheets on this site are in test mode too.

> **Note**
>
> In test mode, the image picker opens the computer’s files, and the chosen images last until you close the page.

## Development mode

To see the sheet **inside the room** while you write it, without installing it again after each change:

1. Install the plugin in the room once.
2. Serve the sheet’s folder with a local server. For example, with Node installed: `npx serve --cors .` (it shows the address, like `http://localhost:3000`).
3. In **Room settings → Plugins**, click **Development** on the plugin and type the address of the sheet’s HTML, like `http://localhost:3000/my-sheet.html`. Click **Save**.

*Screenshot:* The Development screen of the RPG Desk Basic Sheet, with the address http\://localhost:5174/index.html for the Character sheet and the Save button.

- Sheets of that type now come from your computer, **only in your browser**: everyone else in the room keeps the installed version. The sheet shows “Development:” and the address at the top.
- Saved the file? Reload the sheet (close and reopen the tab, or **Reload** if it stops).
- **Turn off**, on the same screen, goes back to the installed version.
- If the page uses `<script type="module">`, the local server must allow CORS (the `--cors` in the example).

Done? Bump the `version` and install the new version for everyone. See [New versions](https://docs.rpgdesk.com/en/fichas/versoes/).

## Page errors

Inside the room, an error in the sheet’s JavaScript does not show up for whoever is playing, but the sheet shows a triangle with the number of errors in the corner. Click it:

*Screenshot:* The Page errors panel, with a TypeError, and the Copy errors and Clear buttons.

- **Copy errors** copies the errors, with the sheet, the plugin and the version: paste them in the conversation with the AI or send them to whoever made the plugin.
- **Clear** empties the list.

## When the sheet does not open

| The message                                             | What to do                                                                                                   |
| ------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------ |
| **The page did not answer. Does it load rpgdesk.js?**   | check the two rpgdesk.js lines in the `<head>` and whether the script breaks while loading                   |
| **The page tried to go somewhere else and was closed.** | a link, a `<form>` or a `location = …` took the page away from the sheet. Use tabs and `RPGDesk.ui.openLink` |
| **The page stopped responding.**                        | an infinite loop or heavy math froze the page. **Reload** tries again                                        |

The [verifier](https://docs.rpgdesk.com/en/referencia/verificador/), at install time, already catches most of these problems beforehand.