XPCOM is an open-source product of mozilla.org. It is used in the also open-source web browser, Mozilla. XPCOM is a cross-platform (XP) software component technology, similar to Microsoft's COM. It provides for the dynamic loading of software components, it has a layout engine using the XUL XML file format, XPCOM components are scriptable through JavaScript using XPCONNECT, and it has a host of other features.
