Mozilla Application Framework

The Mozilla application framework is a collection of cross-platform software components that make up the Mozilla applications. It was originally known as XPFE, an abbreviation of cross-platform front end. It was also known as XPToolkit. To avoid confusion, it is now best referred to as the Mozilla application framework.

While similar to generic cross-platform application frameworks like GTK+, Qt and wxWidgets, the intent is to provide a subset of cross-platform functionality suitable for building network applications like web browsers, leveraging the cross-platform functionality already built into the Gecko layout engine.

The following are the various components of the framework:

Gecko

Gecko is a standard-based layout engine designed for performance and portability.

Necko

Necko provides an extensible API for several layers of networking from transport to presentation layers.

XUL

XUL is the basis of user interface. It is an application of XML that defines various user interfaces elements, mostly widgets, control elements, template, etc. It is similar in many ways to HTML.

XBL

XBL allows one to define his/her own widget for use in XUL.

XPCOM

XPCOM is an object interface that allows interfacing between any programming language for which a binding has been developed

XPConnect

XPConnect is the binding between XPCOM and JavaScript.

XPInstall

XPInstall is a technology for installing small packages like extensions and themes into Mozilla applications in form of installation archives known as XPI.

Web services

Mozilla includes built-in support for popular web services standards XML-RPC, SOAP (dropped since Gran Paradiso Alpha 7), and WSDL as well as a simple XMLHttpRequest object similar to the one in Internet Explorer.

Others

The framework supports a number of open or common standards, including DTD, RDF, XSLT/XPath, MathML, SVG, JavaScript, SQL, LDAP, etc.