Let's Script - User Script & Style Manager

Inject custom JavaScript & CSS into any website — permanently and seamlessly. A next-generation User Script & Style Manager built strictly on Chrome Manifest V3 with a dedicated Side Panel IDE. Take full control of your browsing experience. Write, test, and inject pure JavaScript scripts and custom CSS stylesheets into any web page or local development server with real-time live preview and zero setup friction. Whether you are debugging localhost builds, building custom dark themes, removing page clutter, or automating repetitive web workflows, Let's Script delivers a desktop-grade developer workspace right beside your active tabs. ⚡ MODERN ARCHITECTURE & SEAMLESS MIGRATION • Built From Scratch for Manifest V3: Engineered natively around Chrome's official chrome.userScripts and chrome.scripting APIs. No legacy hacks, no battery drain, and rock-solid stability across browser updates. • One Extension Replaces Two: Eliminate the need to run both a userscript manager and a userstyle manager. Let's Script combines custom JavaScript injection and CSS styling into a single, unified rule manager. • Effortless Transition: Coming from older tools like Tampermonkey, Violentmonkey, or Stylus? Let's Script provides a cleaner, modern environment designed specifically for the MV3 era while maintaining zero-tracking privacy. 🚀 KEY FEATURES • Unified JavaScript & CSS Injection Organize your customizations cleanly. Write pure JavaScript and pure CSS in dedicated tabs with full CodeMirror 6 support: syntax highlighting, autocompletion, bracket matching, and line numbers. • Side Panel IDE (Never Loses Focus) Unlike traditional popup-based managers that disappear when you click the page, Let's Script lives natively in Chrome's Side Panel. Edit code side-by-side with web pages and test changes in real time without tab switching. • localhost & Custom Port Support (No Pattern Errors) Target local development environments directly: http://localhost:3000/ , http://127.0.0.1:8080/ . Chrome's native match pattern system rejects port numbers — Let's Script's two-stage matching engine resolves this automatically. • Precise URL Matching (Wildcards & RegEx) Target pages with extreme accuracy using standard Chrome match patterns (e.g., https://.github.com/), full Regular Expressions, wildcards (*), and per-script exclusion patterns. • USER_SCRIPT & MAIN Execution Worlds USER_SCRIPT World: Isolated from target page scripts, secure, and exempt from strict host Content Security Policies (CSP). Safe for complex sites like YouTube and Google. MAIN World: Direct access to the target page's window object, React/Vue/Angular state, and global variables. • Active Tab Awareness & Real-Time Toggles Instantly see which scripts match the currently open tab. Enable or disable any script on the fly with a single click — updates apply immediately. • Full-Screen Desktop Dashboard Need an expansive workspace for complex scripts? Switch to the two-column split dashboard to search, filter, organize, and inspect 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 sync your setup across machines. • Dynamic Dark & Light Themes Switch effortlessly between high-contrast dark and light themes across the Side Panel, Dashboard, and CodeMirror editor. 💡 WHAT CAN YOU BUILD? 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. Automate repetitive page interactions during daily development. Custom Dark & High-Contrast Themes: Craft sleek custom stylesheets for documentation websites, forums, or legacy internal tools that lack native dark mode. Page Cleaners & Distraction-Free Reading: Hide sticky floating banners, cookie consent popups, newsletter overlays, and distracting sidebar clutter on news sites and blogs. Video Player Customization: Add custom playback speed buttons (1.25x, 1.5x, 2x), glowing neon progress bars, or custom keyboard shortcuts to streaming sites. Web Productivity Utilities: Add "Copy as Markdown" buttons to documentation sites, display repository file sizes on GitHub, or highlight important keywords across pages. 🔒 PRIVACY & ZERO TRACKING • 100% Local Storage: All user scripts, stylesheets, and settings are stored locally on your device via Chrome's native 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: Fully offline. Zero analytics, zero telemetry servers, and zero third-party dependencies. • Safe Isolated Sandboxing: Scripts execute within isolated environments designed by Chrome to preserve page integrity and security. 🛠️ GET STARTED IN 30 SECONDS Click the Let's Script icon in your toolbar to open the Side Panel. Click "+ New Script" to slide open the code editor. Set your script name and target URL pattern (e.g., https://.example.com/ or http://localhost:3000/ *). Write your JavaScript and/or CSS. Click "Save & Activate" — navigate to your target page to see it running live!