JS Mage

About

JS Mage is a utility for injecting custom JavaScript directly into the MAIN execution world of web pages.

It natively bypasses standard extension isolation and Content Security Policy (CSP) restrictions that normally block inline script execution.
This allows your injected code to interact directly with the host page's window object, native variables, and frameworks.

The extension uses a draggable, resizable code editor injected into the active tab via a Shadow DOM, preventing the host page's CSS from breaking the editor's UI.

Core Features
● Execution Scopes: Maintain independent scripts for specific hostnames (Local) or a single script applied across all websites (Global).
● Execution Modes: Run code manually on demand, or toggle "On Load" to automatically inject the script as soon as the DOM finishes loading.
● In-Page Editor: A floating, resizeable editor overlay with adjustable opacity. Includes a custom regex-based syntax highlighter, a built-in code formatter, and an independent undo/redo history stack.
● Theming: 13 built-in syntax highlighting themes, including standard IDE defaults (Dark+, Monokai, Dracula, Nord, One Dark).
● State & Backup: Export individual scripts as .js files, or dump/restore your entire cross-site storage database via JSON.
● Kill Switch: A master power toggle to instantly disable all script injections without losing your saved code.

Controls & Shortcuts
● Click Extension Icon: Toggle the editor UI.
● Double-Click Extension Icon: Toggle master power (Enable/Disable all injections).
● Ctrl/Cmd + Shift + Space: Global shortcut to toggle the editor visibility.
● Ctrl/Cmd + Enter: Execute the current script immediately.
● Ctrl/Cmd + /: Toggle line or block comments.
● Ctrl/Cmd + Z / Shift + Z / Y: Native-style undo and redo.

Note: Because scripts execute in the MAIN world context, disabling the extension's power or removing an auto-run script requires a page refresh to clear previously executed code from the browser's memory.