Wirtschaftsuniversität Wien Magisterarbeit - SemanticLab

6. Development of a Privacy Plug-In
In this chapter, the applied part of this master thesis will be discussed. As already
mentioned earlier, the applied part consists of the development of a Mozilla Firefox
extension or to be precise: an enhancement and up-port of an outdated P3P extension
for Firefox to create a basis for the open source community to further enhance it.
Before describing the initial situation of the project, some general information on extension
development for Mozilla Firefox will be provided. Afterwards, the enhancement
of the existing extension will be briefly discussed. The chapter will then be finished by
the evaluation of the newly developed Firefox extension.
6.1. Add-on development for Firefox
The area of add-on or extension development for Mozilla Firefox is wide and fills books
[Fel07]. That is why in the upcoming part of this thesis, only a brief overview on this
topic can be given. However, this work tries to provide useful resources and references
if the need for in-depth information arises. Parts of this section have originally been
written by the author in [EPAB09].
6.1.1. The extension concept
With its concept of extensions, Mozilla provides a flexible way to add new functionalities
to its products. While this concept is applicable to all Mozilla products (such as Sea-
Monkey, Thunderbird, Sunbird etc), this chapter only deals with Firefox specifics which
may or may not be applicable to other Mozilla products. It has to be highlighted that
extensions are, at least in the Mozilla scope, something different than plug-ins. Plug-ins
deal with more “core”-functionalities of Firefox such as Adobe’s PDF-reader or similar.
Although both extensions and plug-ins can be based on native code (such as C++),
extensions are mostly developed using JavaScript and XUL (pronounced “zool”) which
is an XML dialect [MDC09a].
As just mentioned, extensions are basically based on two technologies: JavaScript and
the XML User Interface Language (XUL). Whereas this thesis is not going to discuss
JavaScript, XUL should shortly be introduced as it is not as well known as JavaScript.
XUL is “Mozilla’s XML-based language that lets you build feature-rich cross platform
applications that can run connected or disconnected from the Internet” [MDC09b]. XUL
basically allows developers to easily create graphical user interfaces (GUI) with all known
elements such as buttons, status-bars, menu-lists, drop-down lists, etc. by using an XML
dialect. Besides drag and drop support, XUL also offers so called ”XUL templates”.
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