Firefox add-ons

One of the most useful aspects of the Firefox web browser is that its architecture lets developers create software add-ons to customise the browser and add many useful features that are not provided as standard (for example, to improve privacy, or provide tools for web developers).

Add-ons which are particularly useful include:

 RequestPolicy   Prevents content from third-party sites being loaded on the site that you are visiting (for example buttons and content from social network sites which track your movements around the web, data-gathering adverts, and so on).
NoScript Prevents untrusted JavaScript (and other plugins, such as Flash, Java, etc) from running, unless permitted.
Flashblock Prevents Flash content from running automatically (unneeded Flash is quite CPU-unfriendly, especially on Linux).
This add-on is not needed if you have NoScript, but it is a simpler solution if you do not.
Firesizer Lets you resize your browser window to a specific size (useful for web development, or if you’re just finicky..).
(In Firefox 31 or newer, The Addon Bar is also required (as this has been removed from Firefox).)
Neo Diggler A “go up” arrow for navigating hierarchical web folders more easily.
It’s All Text Lets you open textarea editing boxes in an external editor.

 

Web Developer
Firebug Web developer debugging and code inspection tool
Colorzilla Colour picker tool, useful for editing stylesheets or transferring colour values from and to images.
Cookie Controller Lets you quickly set cookie acceptance options for individual websites, delete cookies, etc