the interfaces found within this section are not mandatory. this section extends the dom core api to describe objects and methods specific to html documents, and xhtml documents. in general, the functionality needed to manipulate hierarchical document structures, elements, and attributes will be found in the core section; functionality that depends on the specific elements defined in html will be found in this section. elements deprecated since html 4.01 are not listed. some elements and attributes listed here are deprecated in xhtml 1.1. for example, presentation attributes, image maps, frames and targets.