JSXML includes REXML, a high-performance parser that doesn't mind if you throw 2000 lines of (well-formed) XML at it, a builder with a unique API that invites the coding of GUIs (graphical user interfaces) around it, and an iterator that makes costly recursion unnecessary. It was released under the LGPL (it's free for private and commercial use, no strings attached) and has been downloaded over 7000 times.