Mozilla Firefox has become an extremely powerful and useful tool for web developers. Using the right add-ons, it will be developers best dream. Each of these add-ons can make certain things easier and that`s especially important for web-developers, because searching for errors and optimizing your pages can be difficult and time-consuming.

Web Developer`s tool bar probably will become one of the best plugins You`ve ever seen. It comes with his own tool bar that gives many useful tools for analyzing, validating and optimizing web-pages. The great thing about this plugin is that it’s on a few different browsers, so if you switch between them you will be able to use the same plugin on all.
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.

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.

Firebug is one of those extensions that you simply can’t be without. It lets you edit, debug, and view CSS, HTML, and JavaScript.

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,

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.

It allows you to customize the way a webpage displays using small bits of JavaScript.

All browsers include a “View Source” option, but none of them offer the ability to view the source code of external files. You can use the JSView extension to solve the problem. If the website you are viewing contains any external js/css files, an icon will appear that says “SS”, “JS”, or both. Each individual file can then be viewed by clicking on the filename. The file will be opened in a new window.

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.

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.

This add-on lets you preview websites in IE. It helps when checking for cross browser compatibility. You can also set some websites to always open in IE viewer if there are some compatibility issues.

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!

Screengrab saves entire web pages as images. This tool will allow You to take screenshots of what is currently on your screen – you can even choose the portion of the screen you want to “grab”!

Get the feel of Dreamweaver in a Firefox extension. Edit your documents right next to your web pages as you surf.

This tool can be used to clean page from unwanted banners and ads, especially prior to printing a page. Pretty useful for web developers for analyzing the structure of a page.