Hierarchical Select

This module defines the "hierarchical_select" form element, which is a greatly enhanced way for letting the user select items in a hierarchy.

Hierarchical Select has the ability to save the entire lineage of a selection or only the "deepest" selection. You can configure it to force the user to make a selection as deep as possible in the tree, or allow the user to select an item anywhere in the tree. Levels can be labeled, you can configure limit the number of items that can be selected, configure a title for the dropbox, choose a site-wide animation delay, and so on. You can even create new items and levels through Hierarchical Select!

This new form element makes using the Taxonomy, Book, Menu, Content Taxonomy, Subscriptions Taxonomy and Deployment modules so much easier and more pleasant to use.
Second, but definitely not least, it makes selecting items in big hierarchies actually scalable. It easily scales up to thousands of items.
Third, Hierarchical Select degrades completely: all functionality works even when JavaScript is disabled.
However, to really achieve widespread usage across Drupal contrib, it will be necessary to get Hierarchical Select in core; because only then it will actually be used by contrib developers.

Explore Hierarchical Select's features by browsing through the tabs.

Enjoy!

For bug reports and feature or support requests, please use the issue queue, not my contact form. Thanks.

P.S.: The module that powers this demo is available on Github.