Marks: Text Highlighter User Guide

Thank you for using Marks: Text Highlighter. This extension allows you to easily highlight, save, and manage text on web pages.

How to Add Highlights

There are three ways to add highlights to selected text on a web page.

1. Using Control UI

When you select text, a highlight icon (pen shape) appears near the selection. Click this icon or hover over it to reveal the Control UI with a color palette. Click a color to apply the highlight.

Note This works when 'Show Control UI on text selection' is enabled in settings. It is also the primary method for mobile devices.

2. Using Context Menu

Select text and right-click to open the context menu. Navigate to "Marks: Text Highlighter" and select a color to highlight.

Limitation Context menu highlighting is not supported on Firefox for Android.

3. Using Shortcuts

Select text and use keyboard shortcuts to quickly apply colors.

  • Ctrl + Shift + 1 : 1st Color (Default: Yellow)
  • Ctrl + Shift + 2 : 2nd Color (Default: Cyan)
  • ... Number keys 1-4 correspond to the default colors.
Limitation Shortcuts are not supported on Firefox for Android.

How to Delete Highlights

You can remove unnecessary highlights using the following methods:

  • Individual Delete (Control UI): Click on an existing highlight to open the Control UI. Click the Trash icon to delete it.
  • Individual Delete (Popup): Click the extension icon in the toolbar to open the Popup menu. In the "Current Page Highlights" list, click the X button next to the item you want to remove.
  • Clear Page (Popup): Click the "Remove all highlights" button at the bottom of the Popup menu to remove all highlights on the current page.
  • Delete Page (Pages List): In the Highlighted Pages List dashboard, click the "Delete" button on a specific page card to remove all data for that page.
  • Delete All Data (Pages List): Click the Trash icon (Delete All Pages) in the top toolbar of the dashboard to delete all saved highlight data.

Custom Colors

Adding and Changing Colors

You can add your own colors in addition to the 5 default ones.

  1. Click on an existing highlight to open the Control UI.
  2. Click the + button at the end of the color list.
  3. Pick a color from the selector and click "Apply".
Note The + button does not appear in the Control UI when highlighting new text. It only appears when you click on an already created highlight.

Deleting Colors

Deleting individual custom colors is currently not supported. To reset all custom colors:

  • Open the Popup menu and click the "Remove custom colors" button. (This will delete all custom colors except the default 5.)

Minimap

A Minimap is displayed on the right side of web pages that have highlights.

  • The minimap visually indicates the location of highlights relative to the entire page length.
  • Clicking a marker on the minimap instantly scrolls to that highlight's position.
  • You can hide it by turning off the "Show Minimap" switch in the Popup menu.

Highlighted Pages List

A dashboard where you can view and manage all saved highlight information at a glance.

  • Search: Search saved records by page title or URL. Matching text is highlighted in the results.
  • Sort: Sort the list by newest, oldest, etc.
  • Expand/Collapse All: Click the toolbar button to expand or collapse the highlight details of all visible pages at once. The button switches between "Expand all" and "Collapse all" depending on the current state.
  • Delete: Delete individual pages or use the top toolbar button to clear all data.
  • Export/Import: Backup or restore your data via the More actions (…) menu in the toolbar.

Synchronization

Syncs highlight data across devices via your logged-in Google (Chrome) or Firefox account.

How it Works

Adding or deleting highlights on one device automatically reflects on other devices logged in with the same account. In case of data conflicts, the most recent change is preserved.

Limitations

  • Storage Limit: Sync storage has a total limit of 100KB, and a single highlight item cannot exceed 8KB.
  • Eviction Policy: When storage is full, sync data for the oldest updated pages is automatically removed to make space. (Local data is preserved.)
  • Mobile Unsupported: Sync is not supported on Firefox for Android.

Cloud Sync (Beta)

A separate feature for environments that don't support browser-native sync, such as Firefox for Android. Devices are linked using a sync code instead of an account login, and highlight data is encrypted on your device before upload, so the server never has access to the actual content.

How to Use

  1. Click the extension icon in the toolbar to open the Popup, then click the Settings (⚙) icon.
  2. In the "Cloud Sync (Beta)" section of the Settings screen, click "Generate New Code" to create a sync code.
  3. On the other device you want to sync, open the Settings screen and enter the same code in the "Enter sync code from another device" field, then click "Connect".
  4. Turn on the "Cloud Sync" switch on each device to activate syncing. The extension syncs automatically about every 15 minutes, or you can click "Sync Now" to sync immediately.
Caution If you lose your sync code, data backed up to the cloud cannot be recovered. The code is partially masked on screen by default — use "Show" to reveal it in full or "Copy" to copy it to the clipboard. Keep it stored somewhere safe.

Disconnecting: Clicking "Forget Code" in the Settings screen disconnects sync on this device and forgets the sync code.

Note Using browser-native sync and Cloud Sync at the same time is not guaranteed to work correctly. We recommend using only one of the two.

Import & Export

Useful for safely backing up data or moving to another browser.

  • Export: Download all currently saved highlight data as a JSON file.
  • Import: Restore data by selecting a previously exported JSON file.