Here are my 8 fav Firefox extensions (only the ones that i most use when making html, css, js, xml, xsl and web developing):
- View formatted source: easy as the name! You’ll get the source code readable (indented and formatted with color).
- Web Developer: this is the most powerful extension for FF. Here tons of features
- XPath Checker: very useful if you work with XML source file and wanna test some XPath string (for XSL developer). Even works with XHTML source file.
- Aardvark: get information of blocks used into pagecode, remove block and view code of selected block. Very nice!
- ScapBook: this is incredible powerful extension. It lets you save a page (it makes a perfect work since the code is processed and manipulated – no more css-images wrong in saved page) and quickly edit it. With this extension you can easily organize your saved pages (you can save entire page or part of it).
- SearchStatus: it gives you the pagerank value of page you are browsing (google page rank and Alexa Rank).
- Html validator: based on tidy, it shows any html errors and can TIDY your sourcecode. Very useful inline HTML manual.