What is the programming language XUL used for?

XUL computer Language is primarily used to construct Mozilla applications. The name XUL came from the 1984 "ghost Buster" movie where the Sumerian deity Zuul posses Dana Barrett and says the famous line, " there is no Dana, Only Zuul"!!. This is because like Zuul, XUL language uses XML do define an interface of a webpage rather than the document.