1. ColorZilla: If there’s a color on a Web page that you like, ColorZilla will find the precise code for it and allow you to paste it into your coding program. You can also create custom colors with its built-in palette browser. It saves the most-used colors for easy access later on. It’s powerful, it’s simple, it’s a must-have.
2. CSS Validator: CSS Validator adds a right-click option in your browser, sending the CSS to the W3C CSS Validator. It opens the results in a new tab. CSS Validator is a nice tool that will come in handy often.
3. Aardvark: Aardvark lets you select elements from a Web page and perform various actions on them. I use it to analyze the structure of a page. You can also remove and isolate elements or generate DOM code. I highly recommend it.
5. Font Finder: Font Finder allows you to highlight a font you like on any site, right-click on the selection, and after choosing “Font Finder”, view the full CSS text styling of the selection. You can then paste that into your own Web page.
6. CSSViewer: No Web designer should be working without CSSViewer. The add-on informs you of all the CSS information you’ll need from a site. Simply click on the page you want, open it in the Tools menu, and it will display CSS information. I use it almost every day.
8. IE View: As long as you’re running Windows, IE View is a helpful tool. The extension adds an “Open in IE” option in the right-click menu, allowing you to quickly open a site in Internet Explorer. It’s a great way to check how a page looks in both browsers.
9. Java Console: If you want to see how Java applets are running on Web pages, the Java Console is for you. You can monitor and debug applets, and get a full report on their performance.
10. HTML Validator: HTML Validator is an extremely powerful tool available to Windows users only. The add-on gives you feedback about errors on the page. It also lets you know where problems need to be addressed. But unless you’re an advanced Web designer, stay away from this tool. It’s very complicated.
11. LinkChecker: LinkChecker highlights links on any Web site and tells you if the link will direct you to a live site or if it will return a 404. I use it every day.
12. Style Sheet Chooser II: Style Sheet Chooser II replaces Firefox’s built-in style sheet switcher and allows you to pick an alternate style that will persist on all pages of a Web site. It’s not something you’ll use often, but when you do need something of the sort, Style Sheet Chooser II is the way to go.
13. Web Developer: If you install any of the extensions in this roundup, Web Developer should be included. It adds a menu and toolbar to Firefox giving you the option to display a page’s style, view and edit CSS, and much more. No Web developer should be without it.
14. Poster: If you want to debug servers and make HTTP requests, Poster is the tool for you. It’s easy to use, you can set a content type, and within minutes, you’ll have all the information you need to inspect the results of your HTTP query. Useful.
15. Aardvark - A cool extension for web developers and designers, allows them to view CSS attributes, id, class by highlighting page element individually.
17. CSSMate - Firefox extension to edit CSS files.
19. Load Time Analyzer - View detailed graphs of the loading time of web pages in firefox. The graphs display events like page requests, image loading times etc.
20. View Dependencies - Find out all files that were loaded in a webpage with the view dependencies tab in page info.
21. Clipmarks - Easily save portions of webpage with this extension.
22. Codetech - Excellent extension for web page designers, codetech is a web page editor with the look and feel of Dreamweaver.
23. Flash Switcher - Use this extension to avoid reloading between flash plugins.
25. Link Evaluator - Quickly check the links in a page to make they are resolving to live links. Good links show up as green, problem links will show up in red.
26. LiveHTTPHeaders - Adds a way to view the headers to the page info viewing area, will also let you work on new ones in real time.
27. SEOforFriefox - Adds information to your Yahoo and Google searches giving you instant knowledge of the site’s standings with various ranking services for easy reference as you check out your competition.
28. SEOQuake - Gives you a lot of options for checking the ranking of your site to see how you place in various search engines.
29. Window Resizer - Automatically resize your browser window between 640×480, 800×600, 1024×768, 1280×1024, 1600×1200 to see how pages appear at these resolutions.
30. Screen grab - Capture screenshot of any webpage and save it as an image file with this extension.
31. X-Ray - Must have Firefox extension, it allows users to view webpage code with a right-click and shuffle between the webpage and its code easily.
32. OperaView - Just like the infamous IE ab, OperaView lets you view webpages as rendered by Opera without ever leaving Firefox.
33. YSlow for Firebug - YSlow analyzes web pages and tells you why they are slow based on the rules for high performance web sites. YSlow is a Firefox add-on integrated with the popular