• Adblock Plus - blocks adverts
• Aging Tabs - Greys out less recently used tabs
• DownloadHelper - “Download videos and images from many sites”
• Fast Dial - Like Opera's speed dial, but better
• Firebug - The ultimate webdev debugging tool
• **Firecookie** - Adds cookie management to Firebug
• Fireshot - Screenshots of a whole webpage without the browser (even the bits outside the viewport)
• Fission - Page load progress bar in the address bar, like Opera
• Flashblock - Hide all flash elements on a webpage until clicked upon
• Foxmarks Bookmark Synchronizer - Syncs bookmarks between Firefox installs on different computers (see also Using your own server to host the bookmarks)
• FoxyProxy - Highly configurable proxy selection tool, including automatic selection based on url
• Glasser - Adds the Windows Vista glass frame to Firefox. Ideally combined with Hide Menubar
• Hide Menubar - Hides the File/Edit/etc. menu bar by default. Press Alt to view it
• Html Validator - Automatically validates the HTML of pages you visit (or use a whitelist if you only want certain pages validated)
• LastTab - Cycle between tabs in a MRU order
• Locationbar2 - Highlights the domain portion of the address bar, and turns the url into a breadcrumb trail
• NoScript - A whitelist of sites permitted to run JavaScript
• RefControl - Lets you control the Referer header on a per-site basis
• Resizeable Textarea - Adds a drop-handle to textareas so that you can control their size
• Session Manager - Allows you to save and reload multiple browsing sessions
• Stealther - Turn off all the browsers normal cache, history, cookies etc at the click of a button
• Tab Scope - Show previews of tabs on mouse hover, like Vista's taskbar
• Tamper Data - Modify headers and POST data
• Undo closed tabs button - Handy toolbar button to unclose a particular tab
• Web Developer toolbar - quintessential toolbar for webdev
• Gesso fixes the Tablet Input Panel icon issues in Firefox to make it behave like any other application
• Grab and Drag gives Firefox touch-friendly scrolling, making it fit into Windows 7 better

Firefox has an advanced config editor to control all settings in the browser, and is particularly useful for editing settings not available in the usual options dialogs. To access the config editor, visit the about:config url in a new tab.

When visiting an EV-SSL site in Firefox 3, the address bar changes to show the certificate's common name in the green box. It's possible to make Firefox show this information for all SSL certificates (although the box will be blue if the cert is not EV) by setting the following config option:

browser.identity.ssl_domain_display=2

Firefox 3 makes you jump through a lot of hoops to add an exception for an invalid SSL certificate and there is a lot of debate on the Internet over whether or not this is a Good Thing. For competent users, these hoops are little more than an annoyance.

The following config options reduce the number of clicks you have to make in order to add an exception. They make Firefox automatically retrieve the certificate and causes the save permanently checkbox to be ticked by default.

browser.ssl_override_behavior=2
browser.xul.error_pages.expert_bad_cert=true

For doing pen-testing work, it's often helpful to use an intercepting proxy to watch/control the requests made by the browser to a secure web server. Unfortunately, Firefox 3 running on Windows Vista prevents this from working; it displays an alternate SSL certificate verification warning which does not offer the usual workarounds, and prevents you from using the proxy.

The fix for this issue is unbelievable; simply open the advanced config editor, and set the following option:

network.dns.disableIPv6=true

Firefox 2 changed the access key modifier from alt+<key> to shift+alt+<key>, which is impossible to actually use unless you have a million fingers. Luckily it's easy to change back to alt+<key>

ui.key.contentAccess=4

• Chrome Extensions