It’s fast and html/css standards well supported. The greatest feature of firefox is it’s extension infrastructures.

you can find almost everything you needed for your surfing pleasure or web programming.

Here’s a list of them which are always installed with my firefox. You can download them and find more info from by clicking on the links

• Download Statusbar :: Firefox Add-ons
  - Download Statusbar 0.9.5.1. A download manager that put all your downloads’ progress and info on firefox’s status bar.
• Answers :: Firefox Add-ons
  - Answers.com’s firefox add-on
• SearchStatus
  - A great SEO tool that can show current website’s google page rank, alexa ranking and also provide links for your website indexing results and etc.
• Web Developer :: Firefox Add-ons
  - A tool integrates most useful tasks for web developers, such as xhtml/css validation, showing css block table info and etc.
• Autofill Forms :: Firefox Add-ons
  - Fillin your web forms