Boost: JavaScript & CSS Injector

by KS Lau · Developer Tools

Manifest V3 Free

View in Chrome Web Store Data as of 16 Oct 2026

Custom JavaScript & CSS Injector. Edit & inject custom JavaScript and CSS per domain - mobile friendly

Users

−6 in 30 days

Rating

0.0 / 5

unchanged in 30 days

Ratings

0 in 30 days

Store rank

#112K

#93K among extensions

Version

2.5.5

updated 3 May 2026

Users

monthly, 11 months

Latest, 16 Oct 2026: 46 usersMove the mouse over the chart for any month

Ratings count

monthly, 11 months

Latest, 16 Oct 2026: 0 ratingsMove the mouse over the chart for any month

The Chrome Web Store rounds user counts down to the leading digit, so the user line moves in steps. The ratings count is exact and is the better signal of real adoption.

About Boost: JavaScript & CSS Injector

A powerful, mobile-friendly browser extension that allows you to edit and inject custom JavaScript and CSS on any website per-domain. Core Features • Cross-Platform Compatibility: Works seamlessly on desktop browsers (Chrome, Firefox, Edge) and mobile browsers including Orion Browser on iOS • Per-Domain Customization: Apply different JavaScript and CSS scripts to different websites automatically • Real-time Injection: Scripts are injected immediately when enabled - no page reload required • Syntax Highlighting: Professional code editors with JavaScript and CSS syntax highlighting • Mobile-Optimized UI: Responsive interface that adapts to mobile screens with touch-friendly controls • Toggle Control: Easily enable/disable scripts for any domain with one tap • Persistent Storage: Your scripts are reliably saved across browser sessions • CSP Bypass: Works on sites with strict Content Security Policy • Large Script Support: Handles scripts larger than 100KB with chunked storage • Light mode and Dark mode support Perfect for: • Customizing website appearances with CSS • Adding functionality with JavaScript • Removing ads and unwanted elements • Creating custom themes • Automating repetitive tasks