Mozilla straps on its Jetpack

Mozilla Labs have launched Jetpack, a new way of creating extensions for browsers. Jetpack builds on HTML, JavaScript and CSS to provide the platform for add-on developers. By switching to web technologies for extensions, the Labs developers hope to make add-on creation accessible to a wider audience of developers. Jetpack Features, as they are called, can be installed and debugged without restarting the browser and can be debugged in the browser using Firebug. Another advantage of the switch to web technologies is that Jetpack Features should be portable to other Mozilla based applications, such as Fennec, Thunderbird and Songbird. It is also possible that other browser developers could add Jetpack compatibility to their browsers.

For security reasons, a Jetpack Feature will run with only the privileges needed and request for access to resources will be presented in user friendly "social terms". Because the code in Features should be short and readable, the Labs developers suggest that potential security issues should be easy to find with short reviews. A versioned Jetpack API provides access to functions in the browser that are typically outside the domain of JavaScript, such as access to notifications, status bar and tabs. Jetpack Feature's AJAX requests are implemented using the JQuery library, but Jetpack aims to be extensible, with support for third-party tool kits and API libraries.

Dion Almear, one of the developers of Mozilla Labs Bespin development environment, said that Jetpack was being shared with the community to get feedback and build a community around the concept. In the Ajaxian blog, he also gives a short example of creating a Jetpack Feature using Bespin and a newly created Jetpack plug-in, which provides a GMail notifier. Other examples on the Jetpack site include an ad blocker which uses the Adblock Plus block list, along with videos, tutorials and documentation.

(djwm)