Firebug is a free and open-source, complete and powerful Web development auxiliary plug-in for Mozilla's Firefox. The same as Chris Pederick's Web Developer, it added plentiful website designing, developing and testing tools at our fingertips. Web developers can use it to debug, edit or even delete HTML, CSS, DOM, and JavaScript code of any website.

Firebug allows to check and edit HTML tag, view and modify various CSS containers (box model) in a web page; check web page's response time (i.e.: download time) according to different file types; debug and execute JavaScript in real time; monitor network status; and so on. In fact, it has become the right-hand man of JavaScript, CSS, HTML and Ajax programming for a long time. Like an exquisite Swiss Army Knife, Firebug enables users to analyze all internal details of web pages from different perspectives, brings great convenience to Web developers.

Key Features

  • Always at your service
  • Inspect and edit HTML
  • Tweak CSS to perfection
  • Visualize CSS metrics
  • Monitor network activity
  • Debug and profile JavaScript
  • Quickly find errors
  • Explore the DOM
  • Execute JavaScript on the fly
  • Logging for JavaScript
  • ....

Official Demo Video

http://getfirebug.com/video/Intro2FB.ogv

Download URLs

(Homepage)