Version of XHTML standard _css/html

There are three versions of XHTML 1.0, which correspond to three versions of HTML 4.01:

XHTML 1.0 Transitional

XHTML 1.0 Strict

XHTML 1.0 Frameset

The XHTML 1.0 transitional contains all the tags and attributes in the HTML 4.01 transitional. The purpose of introducing the XHTML 1.0 Transitional standard is to enable existing HTML designers and developers to migrate to XHTML without having to undergo too much pain.

The difference between XHTML 1.0 Strict and XHTML 1.0 Transitional is that it implements a more distinct separation between the document structure and the presentation. Unlike XHTML 1.0 Transitional, XHTML 1.0 STRICT forces you to use cascading style sheets to control the appearance of the page.

XHTML 1.0 Frameset documents are intended to be documents that use markup to divide the browser into multiple frames (XHTML 1.0 Transitional and Strict pages cannot contain tags).

The consortium also publishes XHTML 1.1 as the recommended standard (May 31, 2001). XHTML 1.1 is very similar to XHTML 1.0 Strict. The main difference is that XHTML 1.1 can be extended with add-on modules to support new elements. For example, you can generate specific XHTML 1.1 pages that contain MathML (mathematical Markup Language), SVG (Scalable vector language), or elements in custom modules that you create.

Finally, the consortium is developing XHTML 2.0 recommendation standards. Because XHTML 2.0 is still in the drafting phase and no WEB browsers currently support the standard, we don't discuss it in this article.

The ASP.net 2.0 framework and Visual Studio. NET 2005 are oriented to XHTML 1.0 transitional. The standard is the least restrictive of the XHTML standard, and it is the most compatible standard with existing HTML pages. However, you can also generate ASP.net 2.0 pages that target XHTML 1.0 Strict standards or even XHTML 1.1 standards (see the "Configuring XHTML Consistency" section later).

(Note that by default, the Beta 2 version of the ASP.net framework is oriented to XHTML 1.1.) The final version of the ASP.net 2.0 framework will be oriented to XHTML 1.0 transitional. ）