Terms: Create pages and objects thereon using technology defined by formal grammars published in the most recent versions available, when they are supported by user programs. Use elements and attributes so that they conform to specifications, respecting the semantic aspect. In particular, for HTML (HyperText Markup Language) markup languages and XHTML (eXtensible HyperText Markup Language):
a) for all new sites, use at least version 4.01 of HTML, or preferably version 1.0 of XHTM, in any case, with Strict DTD (Document Type Definition);
b) for existing sites, instead of the first application, where it is not possible to comply with point a), it shall be permitted to use the version of the above-mentioned languages with Transitional DTD, but with the following cautions:
1. avoid using, within the markup language in which the page is coded, elements and attributes to define the page's presentation characteristics (for example, characteristics of the text characters, colours of the text and the background, etc.), and use CSS (Cascading Style Sheets) to achieve the same graphic effect instead;
2. avoid generating new windows. Where this is not possible, explicitly warn the user of the change of focus;
3. plan the transition of the entire site to the Strict DTD version of the language used, informing the Prime Minister's Office - Department for Innovation and Technology, and the National Centre for Computing in Public Administration.

WCAG 1.0 References: 3.1, 3.2, 3.5, 3.6, 3.7, 11.1, 11.2
Sec. 508 References: None