RegExe

A browser extension for Zen Browser (Firefox-based) that provides regex-powered find-in-page functionality. It adds a custom search bar with JavaScript RegExp support, match highlighting, color customization, and content copying.

Features

• Dual Regex Modes:
  • Basic Regex (Default) -- search behaves as a regex with automatic global and case-insensitive (gi) flags.
  • Strict JS Regex -- toggle the checkbox to strictly evaluate your input as a Javascript regular expression (e.g. /pattern/flags).
• Match highlighting -- all matches are highlighted on the page with a distinct color for the active match. Uses the CSS Custom Highlight API where supported, with a DOM-based fallback.
• Match navigation -- step through matches with previous/next buttons or Enter/Shift+Enter. A counter displays the current position (e.g. "3 / 17").
• Highlight color picker -- choose from 8 preset colors or pick a custom color. The selection persists across sessions.
• Copy matches -- copy matched content to the clipboard in three formats:
  • Copy HTML (outerHTML of matched elements)
  • Copy Inner HTML (innerHTML of matched elements)
  • Copy Texts (plain matched text, one per line)
• Error handling -- invalid regex patterns are caught and displayed inline without breaking the page.

Installation

Temporary (Development)

1. Open Zen Browser and navigate to about:debugging.
2. Select "This Firefox" from the sidebar.
3. Click "Load Temporary Add-on..." and select the manifest.json file from this project.

Permanent

Package the extension as an .xpi file and install it through about:addons, or submit it to the Firefox Add-ons store.

Usage

Press Ctrl+Shift+F to open the find bar. Alternatively, click the RegExe icon in the browser toolbar.

Type a search query to find and highlight matches on the page. By default, the search operates in Basic Regex mode where any pattern you type (e.g., \w+) is evaluated with automatic global and case-insensitive flags.

Check the "JS Regex" checkbox to switch to Strict mode. In this mode, you must explicitly define your regex flags using JavaScript syntax:

/hello/gi      matches "hello" globally and case-insensitively
/hello/        matches only the first "hello" (case-sensitive)
\d{4}          matches the first 4-digit number it finds (case-sensitive)

Press Escape to close the find bar and clear all highlights.

Project Structure

RegExe/
├── manifest.json            Extension manifest (Manifest V2)
├── background/
│   └── background.js        Command and browser action handler
├── content/
│   ├── content.js           Find bar UI, search engine, highlighting
│   └── content.css          Styles for find bar and match highlights
├── icons/
│   ├── icon-16.png
│   ├── icon-48.png
│   └── icon-128.png
├── LICENSE
└── README.md

Requirements

• Zen Browser or Firefox 109+
• No additional dependencies

License

This project is licensed under the GNU General Public License v3.0. See the LICENSE file for details.

Copyright (C) 2026 Ismail Kulak