Versions of HTML

When designing the last HTML version 4, many HTML documents, or elements and attributes were used for the presentation and were taken into account. The results were eventually given three variants:

Strict
This DTD includes the core set of elements and attributes. It lacks most elements and attributes to influence the presentation, including the elements of font, center, and u, as well as attributes such as bgcolor, align, and target.

Their role will incorporate the documents in strict style sheets. Text and non-block forming elements within the elements of body, form, blockquote and noscript must in principle be within a container element, for example, in a p-element.

Transitional
The Transitional version still contains older elements and attributes that also allow the physical markup. With this DTD Web authors should not separate the logical structure and presentation of each other and be given the opportunity to write standards compliant with HTML. At the same time, it should ensure that existing sites can still be displayed by current web browsers.

Frameset
This version also contains all elements of the Transitional variant but not the elements for the production of framesets.

Future of the variants

With XHTML 1.1, the latest version of HTML, and in the nascent stage of development in XHTML 2.0, the W3 Consortium waived again on the distinction and the only effect was the strict version. Elements that occurred previously, in the Transitional and Frameset variants, will account for nearly all of them.

Such effects must be held by CSS, JavaScript and XFrames which can be achieved using other methods, since they provide logical markup where necessary. An attribute that the Transitional variant expected-creates the “leap” in XHTML 2.0 and is the “value” attributed for numbered list items, which determines the number of the list item itself.