Web Development


JavaScript Debugger

As of Firefox 33, Venkman *no longer works*, as the APIs which it needs have been removed.

Venkman is the code name for Mozilla's JavaScript Debugger. Venkman aimed to provide a powerful JavaScript debugging environment for Mozilla based browsers.

Rated 4 out of 5 stars (50)
8,553 weekly downloads

RESTClient, a debugger for RESTful web services.

Notice: some important features (XML indentation and load old saved requests) are missing in version 2.0.0, please update to version 2.0.1.

Please follow the link ("View other versions") below To install version 2.0.1.

Rated 4 out of 5 stars (82)
7,933 weekly downloads


FirePath is a Firebug extension that adds a development tool to edit, inspect and generate XPath 1.0 expressions, CSS 3 selectors and JQuery selectors (Sizzle selector engine).

Rated 4 out of 5 stars (22)
7,615 weekly downloads

IE Tab

IE Tab - an extension from Taiwan, features: Embedding Internet Explorer in tabs of Mozilla/Firefox...

Rated 4 out of 5 stars (1,191)
7,120 weekly downloads


Draw a ruler across any webpage to check the width, height, or alignment of page elements in pixels.

Rated 4 out of 5 stars (339)
7,023 weekly downloads

Open With Photoshop No Restart

Open With Photoshop is a new companion for web and graphic designers to open up any web image with Adobe Photoshop via a single and quick mouse click.

Rated 5 out of 5 stars (47)
6,837 weekly downloads

Screengrab (fix version) Featured

Screengrab! saves webpages as images.
0.98 released!
New features: upload to internet

Rated 5 out of 5 stars (259)
6,728 weekly downloads

Cookies Manager+

Cookies manager to view, edit and create new cookies. It also shows extra information about cookies, allows edit multiple cookies at once and backup/restore them.

Rated 4 out of 5 stars (74)
6,256 weekly downloads

Live HTTP Headers

View HTTP headers of a page and while browsing.

Rated 4 out of 5 stars (157)
6,131 weekly downloads

ColorfulTabs Featured

The most beautiful yet the simplest add-on that makes a strong colorful appeal. Colors every tab in a different color and makes them easy to distinguish while beautifying the overall appearance of the interface. For Seamonkey & Flock. An essential. F...

Rated 4 out of 5 stars (991)
5,747 weekly downloads

JavaScript Deobfuscator No Restart

This add-on shows you what JavaScript code runs on a web page, even if it is obfuscated and generated on the fly. Simply open JavaScript Deobfuscator from the Web Developer menu and watch the scripts being compiled/executed.

Rated 5 out of 5 stars (20)
5,572 weekly downloads


Autofill is a small but powerful add-on that serves one purpose: fill form fields automatically on page load. It is for people who just want a straightforward form filler without all the bells and whistles.

Rated 3 out of 5 stars (49)
5,567 weekly downloads

One Click Proxy IP No Restart

The easiest way ever to change IP and browse anonymously! Just activate it with one click and it's done, you're browsing the web with a random HTTP or Socks proxy list from several countries in the world. No ads. 100% free to prevent web censorship.

Rated 4 out of 5 stars (24)
5,497 weekly downloads

Fire IE (FireIE, Enhanced IE)

Embeds Internet Explorer(IE) to use the powerful Firefox add-ons.
Not only an enhanced IE Tab, but also an enhanced Internet Explorer with Adblock Plus and FireGestures support.
Switch to the IE engine in one click and dismiss your IE.

Rated 4 out of 5 stars (137)
5,119 weekly downloads

The Addon Bar (Restored) No Restart Featured

Gives you a place to put all your add-on buttons without over-crowding the navigation bar.

Rated 5 out of 5 stars (276)
4,810 weekly downloads

Tiny JavaScript Debugger

TinyJSD is a JavaScript debugger for privileged code running Mozilla products like Firefox, Thunderbird, SeaMonkey. It serves to debug the application as well as extensions written in JavaScript.

Rated 4 out of 5 stars (5)
4,661 weekly downloads

User Agent Overrider No Restart

Override browser user agent string

Rated 4 out of 5 stars (49)
4,608 weekly downloads

Disable WebRTC No Restart

WebRTC exposes your internal network IP(s), without user interaction.

Rated 4 out of 5 stars (21)
4,538 weekly downloads

User-Agent Switcher No Restart

Quickly and easily switch between popular user-agent strings.

Rated 4 out of 5 stars (9)
4,523 weekly downloads

Selenium Expert (Selenium IDE)

This plugin is my attempt to bring the wonderful world of inspections, tips, hints, fixes and refactoring to Selenese! The Selenium Expert goes through your selenium test cases suggesting improvements, giving tips and even lets you apply them.

Rated 5 out of 5 stars (1)
4,312 weekly downloads