I wrote the script for my phpXplorer (www.phpXplorer.org) system. The script is not intended to be a website menu.
Due to use of the DOM the script only works in modern browsers like MSIE > 5.0, Netscape/Mozilla/Firefox and Opera.
Without support for dead Browsers the size of the script is only 12kb and there are no browser switches inside the code.
A funny feature is that the treeview is able to define its data definition by itself.