Paste the above sample code inside your favourite editor and save it with a file extension of .XUL. Open the file in a Mozilla-based browser to view it.
* Line 1: Declares that it is an XML file * Line 2: Used to reference the stylesheets. In this case, the global/skin chrome directories' default global.css file is used. global.css is used to declare all of the XUL elements. * Line 3: Describes a new window to be drawn, using the namespace http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul. All children of this window are XUL. * Line 5: Description tag is like a label, but can wrap many lines. * Lines 6-9: Describes a radio button group. * Line 10: Draws a button.