Web Developer

Adds a menu and a toolbar with varius web developer tools! This is a Firefox extension must have for anyone doing HTML/CSS work.

http://www.chrispederick.com/work/firefox/webdeveloper

tidy

Will detect errors in HTML.

http://tidy.sourceforge.net

Check HTML like this: {{{ lynx -source http://localhost:8081/package1|tidy -eq }}}

Venkman Javascript debugger

"Don't cross the streams!"

http://www.hacksrus.com/~ginda/venkman/

JS Lint

http://www.crockford.com/javascript/lint.html

Put the Javascript console in a sidebar

1. Make a bookmark with this address: chrome://global/content/console.xul
2. Go to Bookmarks->Manage Bookmarks, right-click the new bookmark, select Properties
3. Check the ‘Load this bookmark in the sidebar’ box