Portable Firefox is a fully functional package of Firefox optimized for use on a USB key drive. It has some specially-selected optimizations to make it perform faster and extend the life of your USB key as well as a specialized launcher that will allow most of your favorite extensions to work as you switch computers. It will also work from a CDRW drive (in packet mode), ZIP drives, external hard drives, some MP3 players, flash RAM cards and more.
This is an unofficial package. It is an official build, but has been modified and a specialized launcher added to make extensions portable. No warranty is expressed or implied.
To install, just download the ZIP and unzip it to the root directory of your USB drive. It will create a "firefox" directory and all the requisite directories underneath. To use Firefox on your drive, launch it with the PortableFirefox.exe file in the firefox directory. DO NOT launch the firefox.exe file directly, as this will create a profile on your hard drive or use an existing one. Additionally, be sure you've closed any local copies of Firefox and that they've finished shutting down. Otherwise, a new window of your local install will be launched. This is a feature of Firefox itself to prevent multiple copies running at the same time.
Portable Firefox是一个可以在便携USB驱动器上使用的全功能，充分优化过的Firefox。通过一些经过专门选择的优化，使的它执行更迅速，扩展你的便携 式USB驱动器的用途同时通过这个专门的工具，在更换电脑后，可以使你继续使用大部分原有的收藏夹。通过CD驱动器（外置型），ZIP驱动器，外置硬盘， 某些MP3播放器，闪存卡以及其它便携设备也可以正常使用它。
Homepage: http://portableapps.com/apps/internet/firefox_portable
Download: Portable Firefox v2.0.0.9(英文版)
Download: Language Packs
News source: 中文化方法参考