This document discusses JavaScript improvements and changes in Drupal 7. It outlines problems with JavaScript in Drupal 6 and provides solutions implemented in Drupal 7, such as a standardized way to add JavaScript through libraries and behaviors, improved AJAX support through a new framework, and core inclusion of jQuery UI. Behaviors can now be attached and detached, and there are standardized methods for JSON encoding, adding settings to AJAX responses, and ensuring behaviors are only attached once.