1. Firebug
The most popular and powerful web development tool
- Inspect HTML and modify style and layout in real-time
- Use the most advanced JavaScript debugger available for any browser
- Accurately analyze network usage and performance
- Extend Firebug and add features to make Firebug even more powerful
- Get the information you need to get it done with Firebug.
2. ColorZilla 2.0.2 by Alex Sirota
With ColorZilla you can get a color reading from any point in your browser, quickly adjust this color and paste it into another program. You can Zoom the page you are viewing and measure distances between any two points on the page. The built-in palette browser allows choosing colors from pre-defined color sets and saving the most used colors in custom palettes. DOM spying features allow getting various information about DOM elements quickly and easily. And there’s more…
3. FireFTP 1.0.9 by Mime Čuvalo
Along with transferring your files quickly and efficiently, FireFTP also includes more advanced features such as: directory comparison, syncing directories while navigating, SFTP, SSL encryption, search/filtering, integrity checks, remote editing, drag & drop, file hashing, and much more!
4. Session Manager 0.6.8.3 by Morac
Session Manager saves and restores the state of all or some windows – either when you want it or automatically at startup, after crashes or periodically. It can also automatically save the state of open windows individually.
This extension replaces SessionSaver and Tab Mix Plus’ session manager. It stores more data than both of them and should be more reliable in saving and restoring. Although it is not recommended to have more than one session related extension installed, Session Manager is compatible at least with Tab Mix Plus. It can import sessions from both SessionSaver and Tab Mix Plus.
5. Gmail Manager 0.6 by Todd Long
The original Gmail notifier for multiple accounts. Allows you to receive new mail notifications along with viewing account details including unread messages, saved drafts, spam messages, labels with new mail, space used, and new mail snippets.
6. Html Validator 0.8.6.1 by Marc Gueury
HTML Validator is a Mozilla extension that adds HTML validation inside Firefox and Mozilla. The number of errors of a HTML page is seen on the form of an icon in the status bar when browsing.
The extension can validate the HTML sent by the server or the HTML in the memory (after Ajax execution).
7. Greasemonkey 0.8.20100408.6 by Anthony Lieuallen, Aaron Boodman, Johan Sundström
Allows you to customize the way a webpage displays using small bits of JavaScript.
8. Load Time Analyzer 1.5 by Google
The Load Time Analyzer allows developers to measure and graph how long web pages take to load in Firefox.
Load Time Analyzer produces graphs that show the occurrence of events such as requests for the page, images, stylesheets and scripts, along with events like the execution of an onload script. Use it to tune the performance of your page or to help make Firefox better.
9. Web Developer 1.1.8by chrispederick
The Web Developer extension adds a menu and a toolbar with various web developer tools.
10. Window Resizer 1.0 by Yellowpipe Web
The Browser Window Resizer is useful for testing different screen sizes. It accurately resizes your browser so you can test to see what a web page looks like in all of the standard resolution sizes.
Supports the 640×480, 800×600, 1024×768, 1280×800, 1280×1024, 1600×1200 resolutions.
Resize the current page via the Context menu, Tool menu or Toolbar button.
11. Html Validator 0.8.6.1 by Marc Gueury
HTML Validator is a Mozilla extension that adds HTML validation inside Firefox and Mozilla. The number of errors of a HTML page is seen on the form of an icon in the status bar when browsing.
