Several contrib modules listed in the Utility section offer more JavaScript and jQuery functionality.

• jQuery UI: A wrapper module around the jQuery UI effects library that lets module developers add swooshy, swishy effects to their code.
• Javascript Tools: Javascript Tools provides both an integrated set of JavaScript and AJAX modules and a common set of methods extending those available in Drupal core (drupal.js) for JavaScript and AJAX module development in Drupal.
• jQuery Update: This module facilitates the upgrade jQuery in Drupal 5. jQuery 1.0.4 is included with Drupal 5, however it is not very well supported in the jQuery community. In order to use most current and advanced jQuery functionality you will want to build off a newer version of jQuery. This module includes John Resig's compat-1.0.js plugin that provides backwards compatiblity for newer versions of jQuery to work with the JS code in Drupal 5.
• Ajax Load: When loading new content via AJAX, there is the potential need to load CSS and JavaScript files and data not already available on the page. Ajax Load is a helper module designed to handle this task.
• jQuery Interface: Interface is a collection of rich interface components which utilizes the lightweight JavaScript library jQuery. With these components you can build rich client web applications and interfaces with the same simplicity as writing JavaScript with jQuery. This module simply places Interface in a central location with one command that can be called by any module that wants to use the library.
• jQuery Interface Sortable: The Interface Sortable module makes it easy for developers to add JavaScript drag-and-drop form elements to forms and drag-and-drop widgets to non-form pages. It depends on the jQuery Interface module which in turn relies on the jQuery Update module.
• S/P Ajax: this module introduces effects using the increasingly popular Scriptaculous library, built on Prototype. S/P Ajax includes numerous effects, including draggable page elements, pulsing message, and even expanding menus (through the helper module S/P Magic Menus).
• AHAH Forms Framework: Ahah forms is a utility module, for adding Ajax/JavaScript driven incremental page reloading, without needing to write any JavaScript.
• Spry Framework: Adobe JavaScript library for web designers that provides functionality that allows designers to build pages that provide a richer experience for their users. It is designed to bring Ajax to the web design community who can benefit from Ajax, but are not well served by other frameworks.
• onBeforeUnload API: This module is aimed to avoid incompatibilities between modules that need to bind a handler to the beforeunload event of the window.