Flavors of HTML and XHTML

There are many versions of HTML and XHTML in existence (see Table 3-1). In the early days, the specification of HTML was somewhat fluid, and browser vendors of all sizes added their own elements. First the Internet Engineering Task Force (IETF) and later the World Wide Web Consortium (W3C) set standards for HTML and its cousin XHTML.

Version	Specification URL	Description
HTML 2.0	www.w3.org/MarkUp/html-spec/html-spec_toc.html	Classic HTML dialect supported by browsers such as Mosaic. This form of HTML supports core HTML elements and features such as tables and forms, but does not consider any of the browser innovations of advanced features such as style sheets, scripting, or frames.
HTML 3.0	www.w3.org/MarkUp/html3/Contents.html	The proposed replacement for HTML 2.0 that was never widely adopted, most likely due to the heavy use of browser-specific markup.
<br>	none	none