DHTML eXtensions - professionalonal AJAX components for advanced Web UI.
dhtmlxTree (DHTML extensions Tree) is a feature rich JavaScript tree menu that allows you to effortlessly create attractive and fast-loading hierarchical interfaces with cross-browser compatibility, AJAX support, in-line node editing, and drag-n-drop capabilities.
Rich client-side API provides complete control over the tree appearance and behaviour. Since version 2.5, in addition to the existing functional API, dhtmlxTree also provides object constructor that allows developers to define object properties within a single command.
Special techniques implemented into the component make loading of really big trees fast and effective. Smart Rendering - allows avoiding performance problems in trees with great number of nodes per level.
Advanced drag-and-drop makes it possible to drag items not just within one tree, but between different ones (even if trees are located in different frames or iframes). You can try this functionality right now: