Jetpack
Jetpack 0.2.1 for Windows
Atul Varma Browser & Email / Browser Tweak
Explore new ways to extend and personalize the Web
Jetpack lets you build Firefox (and more!) extensions with the same skill-set you already know from building on the open Web: Javascript, HTML, and CSS. We've even got jQuery included by default to ease you into it. Jetpack is a newly formed experiment in using open Web technologies to enhance the browser, with the goal of allowing anyone who can build a Web site to participate in making the Web a better place to work, communicate and play. Briefly, Jetpack is an API that will allow you to build Firefox add-ons using only the web technologies you are already familiar with.
Firefox

Software Summary:

You can run Jetpack on Windows operating systems. Jetpack is a software product developed by Atul Varma and it is listed in the Browser & Email category under Browser Tweak. Jetpack is a free software product and it is fully functional for an unlimited time although there may be other versions of this software product.

Alternatives in Browser & Email on Windows