As a result of the popular demand for these two Firefox extensions on my 10+ Firefx Extensions for Developers and Bloggers, I have gone ahead and added these two extensions to that list.

1. FireBug - Edit, debug, and monitor CSS, HTML, and JavaScript live in any web page.
2. Web Developer Toolbar - Adds a menu and a toolbar with various web developer tools. I used this add-on for a long time prior to Firefox 2.0. I found its pixel measuring tool to be useful and back when I did table design I used its outlining/bordering tool to help me adjust that flow-based layouts. I’ll have to relearn how to use this sucker for the new methodologies I use for client-end design.

Enjoy! Please add any others and I will append them to the list.

Firefox’s variety of useful extensions makes it the browser of choice for many website developers and blog operators. I’ve used Firefox for close to five years now and I’ve utilized a number of extremely helpful third party plug-ins and extensions to simplify development and website operation.

Today I’m going to run down my list of the 10 extensions that I’ve used and found to be the most helpful.

EDIT: I’ve added Firebug and Web Developer Toolbar to this list, by popular demand.

1. FireBug - Edit, debug, and monitor CSS, HTML, and JavaScript live in any web page.
2. Web Developer Toolbar - Adds a menu and a toolbar with various web developer tools. I used this add-on for a long time prior to Firefox 2.0. I found its pixel measuring tool to be useful and back when I did table design I used its outlining/bordering tool to help me adjust that flow-based layouts. I’ll have to relearn how to use this sucker for the new methodologies I use for client-end design.
3. Seoquake - Seoquake is one of the most powerful tools available for analyzing your website’s Search Engine Optimization results. It will help you determine what your Google PageRank score is, how many pages on your site are indexed, how many external sites link to yours, similar statistics for Yahoo and Live.com, your Alexa ranking, your del.icio.us vote count (for specific pages), and mountains of other data. I’m still finding out more and more about this tool, but I think this is by far and large one of the most powerful extensions available to web developers.
4. ColorZilla - Have you ever seen a really interesting color on a website and try to find out what it is? ColorZilla gives you the ability to simple use a “color picker” to mouse over the desired color and capture it’s hex value. This extension has proved to a real time saver and I’ve used it longer than any of the other extensions or plug-ins on this list (since late 2004).
5. Alexa Sparky - Another traffic analysis tool, brought to you by Alexa, Amazon.com’s traffic ranking service. I like this plugin simply because of the trend graph that it places in the bottom right corner of your browser window, but it also has some helpful features, such as determining what sites are similar to yours.
6. Session Manager - I keep many tabs open on my Firefox sessions at all times, and if my computer has to restart or if something crashes I can lose potentially valuable information if I am unable to find those pages again. Session manager automatically saves your sessions and in the event of a crash or a reboot it can restore all of the tabs in the session for you.
7. IE View Lite - There are a lot of developers out there who wish Internet Explorer would either accept the W3C standards or just go away, but unfortunately a large portion of Internet users are Internet Explorer users. IE View Lite allows you to right click on any given page and gives you the option to view this page in a new Internet Explorer window. IE View Lite is a powerful tool for cross-browser testing and validation. I prefer using IE View over IE Tab, which runs Internet Explorer within a tab in Firefox, simply because IE tab has some quirks (i.e. it reverts back to Firefox if you press Firefox’s reload button while focused on an IE Tab) and you don’t get full access to all of IE’s options with IE Tab.
8. FireFTP - FireFTP is simply an FTP client built into the Firefox browser. It’s free, it’s simple, it’s reliable, and I can flip to FireFTP just like any other tab on the browser.
9. Greasemonkey - Greasemonkey is arguably the most powerful Firefox extension. Greasemonkey allows you to apply custom JavaScripts to pages within your browser; for instance there are scripts to declutter your Facebook homepage, hide Gmail lables, and hide Netflix reviews. I use Greasemonkey to make it easier to navigate social network sites when promoting my blog. You can view the directory of Greasemonkey scripts at Userscripts.org.
10. Download Status Bar - When I download Wordpress plug-ins for my blog, I usually do so in intervals of 3-5 plug-ins at a time. I use Download status bar to give me instant access to my completed downloads without having to hunt them down using Windows Explorer. I try to save time in every way possible.
11. StumbleUpon - While I don’t believe in spamming social tagging sites in everyway possible, I always make sure I am the first to submit my own articles to StumbleUpon. Why? Because the first StumbleUpon review is crucial to getting the correct demographic to view your site, since the categorization of the “stumble” occurs during the first review instance. It’s better that you, the author of the site, write the first review and categorize it accordingly, rather than put it in the hands of someone who may be viewing your site for the first time. In addition StumbleUpon sends more users to your site on average than Digg does, according to ProBlogger.
12. Extended Cookie Manager and Cache Status - I use the Extended Cookie Manager and the Extended Cache Manager to help me debug my site when I’m running into connectivity issues, such as the trouble I ran into with my MySQL connection bombing out in IIS.

Just to let you guys know that I’m not full of it, here’s a screenshot of the extensions list on my desktop after I reloaded it.

What are your favorite Firefox extensions or add-ons? I’ll check em out and release a new list down the stretch!