If the tree has hundreds of nodes, subnodes can be asynchronously loaded on client-side and then displayed by portions on demand. It's possible due to Distributed Parsing functionality implemented in dhtmlxTree. Another feature that solves performance problems in trees with great number of nodes per level is Smart Rendering.
This DHTML tree has checkbox system in order to use this component as a navigation bar with selection lists. Besides usual two-state checkboxes (checked item, unchecked item), there is a possibility to use three state checkboxes with â€œpartly-checkedâ€� value (some sub-items are checked).
dhtmlxTree is distributed under both GPL and commercial license (PRO edition). Source code is available.