COOLjsTree
COOLjsTree is an advanced cross-browser JavaScript tree menu that provides with some unique features that are not to be found elsewhere. Easily adjustable and configurable from the control file it requires no programming knowledge from the user and can be integrated into the site in minutes. Almost every aspect of the tree you can build with this API can be modified and tuned. On-line structure builder further simplifies the process. Documentation and first class support from the vendor also provided. Besides free version there is also COOLjsTree PRO edition with even more features.