The official foldertree, a Javascript utility for displaying menus - Multi-OS Shareware $20. A Javascript utility for displaying tree and cascading menus. It is distinguished by the range of browsers supported (version 3 and upwards of Internet Explorer and Netscape Navigator, plus Opera), performance (it can handle trees with many thousands of nodes), and a multitude of user interface style options.

Most importantly, it is fully supported by dedicated experts. It has been used in complex situations, and has been linked to CGI scripts and databases. It comes with an extensive set of examples.