Install Firefox 9 on Ubuntu 11.10/12.04/11.04/Linux Mint

Install Firefox 9 on Ubuntu 11.10 Oneiric/Ubuntu 12.04 Precise Precision/11.04/Linux Mint 12

What’s New in Firefox
The latest version of Firefox has the following changes:

• Added Type Inference, significantly improving JavaScript performance
• Added support for querying Do Not Track status via JavaScript
• Added support for font-stretch
• Improved support for text-overflow
• Improved standards support for HTML5, MathML, and CSS
• Fixed several stability issues
• Fixed several security issues

To install Firefox 9 on Ubuntu/Linux Mint open Terminal (Press Ctrl+Alt+T) and copy the following commands in the Terminal:

Terminal Commands:
sudo add-apt-repository ppa:ubuntu-mozilla-security/ppa
sudo apt-get update
sudo apt-get install firefox

For Ubuntu Lucid and Maverick, Firefox 9 should be available in the Firefox Stable Channel PPA soon: "ppa:mozillateam/firefox-stable" (in fact, the packages have already been built successfully, but publishing has been disabled for the PPA for now).