The fact that it created structured documents enabled Interleaf to add its Active Document capabilities in the early 1990s. Just as JavaScript enables contemporary software developers to add functionality and "intelligence" to Web documents, Interleaf used LISP to enable document authors and engineers to enhance its authoring electronic publishing systems. Any document element could be given new "methods" (capabilities), and could respond to changes in the content or structure of the document itself. Typical applications included documents that automatically generated and updated charts based upon data expressed in the document, pages that altered themselves based on data accessed from databases or other sources, and systems that dynamically created pages to guide users through complex processes such as filling out insurance forms.