Firefox Browser Add-ons
  • Extensions
  • Themes
    • for Firefox
    • Dictionaries & Language Packs
    • Other Browser Sites
    • Add-ons for Android
Log in
Preview of JS Disector

JS Disector by dukevin

Live JavaScript inspection, replay, modifying, and request/response interception, in Firefox DevTools.

0 (0 reviews)0 (0 reviews)
Download Firefox and get the extension
Download file

Extension Metadata

About this extension
Ever open Firefox DevTools knowing the behavior you want to understand is somewhere in the page’s JavaScript, but tracing callbacks, global variables, event handlers, and network requests is more effort than the problem deserves?
JS Disector was created after one too many mandatory online training sites with unskippable videos and client-side quizzes. The JavaScript was running right in front of me, but still felt just out of reach: I could read the source, add breakpoints, and dig through objects, but there wasn’t a convenient way to watch everything happen, change it, and try it again.
JS Disector adds a runtime-inspection panel to Firefox DevTools. It lets you:
- Watch JavaScript function calls happen in real time
- Explore calls as nested trees
- Inspect arguments, values, timing, and source locations
- Edit values and replay captured calls
- Monitor and modify global variables
- Pause network requests and responses, edit them, and continue
- Disable selected functions or network endpoints
- Search, filter, and save captured behavior
- Ask an optional AI agent to analyze the evidence

It is useful for debugging unfamiliar or badly structured applications, understanding event and data flow, experimenting with browser games, and demonstrating why websites should never trust client-side state for authorization, membership, scores, or other sensitive decisions.

Also - fully open source: https://github.com/dukevin/js-disector
Rated 0 by 0 reviewers
Sign in to rate this extension
There are no ratings yet

Star rating saved

5
0
4
0
3
0
2
0
1
0
No reviews yet
Permissions and data

Required permissions:

  • Extend developer tools to access your data in open tabs
  • Access browser tabs
  • Access browser activity during navigation
  • Access your data for all websites

Required data collection, according to the developer:

  • Website content
Learn more
More information
Add-on Links
  • Support Email
  • Copy add-on ID
Version
0.2.0
Size
3.2 MB
Last updated
11 days ago (Jul 21, 2026)
Related Categories
  • Web Development
License
GNU General Public License v3.0 only
Version History
  • See all versions
Add to collection
Report this add-on
Go to Mozilla’s homepage

Add-ons

  • About
  • Firefox Add-ons Blog
  • Extension Workshop
  • Developer Hub
  • Developer Policies
  • Community Blog
  • Forum
  • Report a bug
  • Review Guide

Download

  • Download Firefox
  • Windows
  • macOS
  • iOS
  • Android
  • Linux
  • All

Latest Builds

  • Nightly
  • Beta

Firefox for Business

  • Enterprise

Community

  • Connect
  • Contribute
  • Developer

Follow

  • Instagram
  • YouTube
  • TikTok
  • Bluesky
  • Podcast
  • Privacy
  • Cookies
  • Legal

Except where otherwise noted, content on this site is licensed under the Creative Commons Attribution Share-Alike License v3.0 or any later version.