Let's Script - User Script & Style Manager

Run custom JavaScript and CSS on any web page based on URL patterns.

Let's Script is a modern, lightweight, and powerful User Script & Style Manager built strictly for Google Chrome based on Manifest V3. Take full control of your browsing experience. Write, test, and inject custom JavaScript scripts and CSS stylesheets into any web page or local development server with zero hassle and real-time feedback. Whether you want to enhance web video players, build custom dark themes, clean up cluttered websites, automate repetitive daily tasks, or debug local development builds on localhost, Let's Script provides a desktop-grade IDE experience right beside your favorite web pages. ⚡ WHY CHOOSE LET'S SCRIPT? Unlike traditional script managers with disappearing popups or clunky interfaces, Let's Script lives natively in Chrome's Side Panel. This allows you to write code side-by-side with web pages, tweak styles live, and see instant results without ever switching tabs or losing your context. 🚀 KEY FEATURES & CAPABILITIES • Integrated Side-by-Side Editor Write and debug scripts directly inside Chrome's Side Panel powered by CodeMirror 6. Enjoy a fast, responsive editor that never disappears when you click on the page. • Dual-Tab Interface (JavaScript & CSS) Organize your customizations cleanly. Write pure JavaScript and pure CSS in dedicated tabs with full syntax highlighting, autocompletion, bracket matching, and line numbers. • Active Tab Awareness & Instant Toggles Let's Script automatically detects which scripts match the currently visited website. See matching rule counts in real time and toggle scripts on or off with a single click. • Two-Stage URL Matching (Wildcards, Regex & Localhost:Port) Target websites with extreme precision using Chrome match patterns (e.g., https://*.github.com/*), full Regular Expressions (RegEx), wildcards (*), and local development servers with custom port numbers (e.g., http://localhost:3000/*). • Isolated & Main Execution Worlds Choose the exact runtime environment for your script: - USER_SCRIPT World: Isolated from target page scripts, secure, and exempt from strict host Content Security Policies (CSP). - MAIN World: Direct access to the page's global window object, frontend frameworks (React, Vue, Angular), and JavaScript variables. • Full-Screen Desktop Dashboard Need more space for complex scripts? Switch to the expansive, two-column full-screen dashboard (options page) to search, organize, inspect, and manage your entire script library. • 1-Click Backup & Migration (JSON Import/Export) Export all your custom scripts, stylesheets, and preferences to a clean JSON file with one click. Safely restore or migrate your setup across browsers and devices. • Seamless Dark & Light Themes Switch effortlessly between high-contrast dark and light themes matching your browser and operating system settings. • Manifest V3 Native & Future-Proof Built strictly upon Chrome's official chrome.userScripts and chrome.scripting APIs. High performance, zero battery drain, and resilient against browser restarts. 💡 POPULAR USE CASES — WHAT CAN YOU BUILD? 1. Video Player Customization: Add custom playback speed buttons (1.25x, 1.5x, 2x), glowing neon progress bars, or keyboard shortcuts to YouTube and streaming sites. 2. Web Page Cleaners & Reader Mode: Hide sticky floating banners, cookie consent popups, newsletter overlays, and distracting sidebar clutter on news and blog websites. 3. Developer & QA Productivity: Auto-fill login forms and test data on staging environments (localhost:3000, 127.0.0.1, internal dev servers) with one-click actions. 4. Custom Dark & High-Contrast Themes: Craft sleek custom stylesheets for documentation websites, forums, or legacy internal tools that lack native dark mode. 5. Productivity Boosters: Add "Copy Code as Markdown" buttons to StackOverflow, display repository file sizes on GitHub, or highlight important keywords across web pages. 🛠️ HOW TO GET STARTED (IN 30 SECONDS) 1. Click the Let's Script extension icon in your Chrome toolbar to open the side panel. 2. Click the "+ New Script" button to slide open the code editor. 3. Enter a script name and specify your target URL pattern (e.g., https://*.example.com/* or http://localhost:3000/*). 4. Write your JavaScript and CSS in the respective tabs. 5. Click "Save & Activate". Navigate to your target page to see your script running live! 🔒 PRIVACY & SECURITY FIRST Let's Script was designed from day one with a strict zero-tracking philosophy: • 100% Local Storage: All user scripts, stylesheets, and settings are stored locally on your device via Chrome's storage engine. • Zero Data Collection: We do not collect, store, track, or transmit any personal data, browsing history, visited URLs, or code. • No External Network Calls: Let's Script operates 100% offline without connecting to any remote analytics or telemetry servers. • Safe Isolated Sandboxing: Scripts execute within isolated user script worlds designed by Chrome to preserve page integrity and security.