I've been working on a new Web site for the past few weeks. But instead of doing it alone, I decided to get some help from Firefox extensions. They've made my work a lot easier, and they all can be downloaded in just a few seconds.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
YSlow: YSlow requires FireBug to be installed for it to work, but it's a great way to find out why your site is running so slowly. It analyzes Web pages and returns issues that are slowing the site down, based on Yahoo's rules for high-performance Web sites. I use it often to find out where I can improve the speed of my sites. Try it out.