Pimp your Firefox with free Internet Development tools

Thanks to the Classes.org email newsletter I received the following list of Internet Development tools that can be added to Mozilla Firefox.

Mozilla Firebug is one that I've been using for a couple of months now and have raved about it in my blog before. It's excellent for working with CSS and you can even change things live. Here are a few more tools that I will be checking over the next couple of weeks. And best of all its all FREE - thank you FireFox.

FirePHP

Extension of the Firebug add-on to show PHP debug information on Firebug console.
https://addons.mozilla.org/en-US/firefox/addon/6149

- YSlow

Currently another extension of the Firebug add-on to measure page loading times and identify problems that make your pages load slower.
https://addons.mozilla.org/en-US/firefox/addon/5369


- Web Developer

Several tools like disabling Java-script, CSS, redirection, clearing browser caches, resizing the browser window to test pages with different sizes, etc..
https://addons.mozilla.org/en-US/firefox/addon/60

- User Agent Switcher

Switch the browser identification to test how sites respond to different browsers.
https://addons.mozilla.org/en-US/firefox/addon/59

- HTML Validator

Validate page HTML to help finding page generation errors cause by eventual bugs in the PHP scripts.
https://addons.mozilla.org/en-US/firefox/addon/249

- Java-Script debugger

Run page Java-script code with single step support and ability to show Java-script variable values during debugging.
https://addons.mozilla.org/en-US/firefox/addon/216

- LiveHTTPHeaders

Show page request and response headers.
https://addons.mozilla.org/en-US/firefox/addon/3829