New interaction paradigms and complex user interface controls of AJAX have raised concerns about access and usability for users of all backgrounds and abilities. Client-side JavaScript code may assume certain language or cultural conventions, alienating vast audiences. Graphical and mouse-based user interaction is often assumed preventing use by keyboard or assistive technology users. This presentation will review the issues and provide best practices for building accessible and globalized AJAX applications today, including the new W3C Accessible Rich Internet Application (ARIA) specification. This and other strategies used to provide full accessibility and globalization in the Dojo Toolkit will be shown.