Displays a country flag depicting the location of the current website's server and provides a multitude of tools such as site safety checks, whois, translation, similar sites, validation, URL shortening, and more...
The Web Developer extension adds various web developer tools to the browser.
Color tools for web development.
Color picker and eyedropper + saving colors and trying out colors with drag and drop.
HTML Validator is a Mozilla extension that adds HTML validation inside Firefox and Mozilla. The number of errors of a HTML page is seen on the form of an icon
For Firefox 23+, you need 0.958 (under review)
Collections are groups of related add-ons that anyone can create and share.Explore Collections