Open & inject
Click a saved entry to open the URL and inject after load. Empty CSS/JS means open-only.
Extension
RunJS
Bind CSS and JavaScript to any URL. Open from the popup or Console, then inject after the page lands. Leave code empty to open the URL only — no site access required.
Why RunJS
One-click workflows for sites you use every day
Save a name, target URL, and optional CSS/JS in the Console. Everything stays on your device — no cloud library, no ads, no tracking.
Local library
Scripts, preferences, and drafts stay in Chrome storage on this computer.
Real-page ready
Follows redirects, supports SPAs and iframes, with configurable inject timing.
Features
What you can do
- Console — library with General / CSS / JS / Settings, CodeMirror editor, format, URL test, and draft restore.
- Popup — search and filter; click to open-and-inject, or open only when code is empty.
- Injection — host + path-prefix match; isolated or page-main world; start / DOM ready / load / idle / delay; persist across refresh.
- Library tools — import/export JSON, batch delete, drag reorder, conflict handling on import.
Requirements
Chrome 135+
To inject saved scripts on Chrome 138+, open chrome://extensions → RunJS details → enable
Allow User Scripts. Site access is requested only for origins where you saved inject code.
Get started
Install from the Chrome Web Store when the listing is live, or review the privacy policy first.