XHTML standard version _ CSS/HTML

The XHTML standard version has three versions of XHTML 1.0, which correspond to HTML 4.01 of the three versions respectively:

• XHTML 1.0 Transitional

• XHTML 1.0 Strict

• XHTML 1.0 Frameset

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

The difference between XHTML 1.0 Strict and XHTML 1.0 Transitional is that it implements a more obvious separation between the document structure and representation. Unlike XHTML 1.0 Transitional, XHTML 1.0 Strict forces you to use Cascading Style Sheets to control the page appearance.

The XHTML 1.0 Frameset document is intended to be a document that uses tags to divide browsers into multiple frameworks (the XHTML 1.0 Transitional and Strict pages cannot contain tags ).

W3C also released XHTML 1.1 as the Recommendation Standard (May 31, 2001 ). XHTML 1.1 is very similar to XHTML 1.0 Strict. The main difference between the two is that you can use additional modules to expand XHTML 1.1 to support new elements. For example, you can generate a specific XHTML 1.1 page that also contains elements in MathML (Mathematical Markup Language), SVG (Scalable Vector language), or created custom modules.

Finally, W3C is developing the XHTML 2.0 Recommendation Standard. Because XHTML 2.0 is still in the drafting stage and no Web browser currently supports this standard, we will not discuss it in this article.

ASP. NET 2.0 Framework and Visual Studio. NET 2005 for XHTML 1.0 Transitional. This standard is the least restrictive in the XHTML standard and is the most compatible with existing HTML pages. However, you can also generate ASP. NET 1.0 pages for the XHTML 1.1 Strict standard or even the XHTML 2.0 standard (see the "Configure XHTML consistency" section later ).

(Note that by default, Beta 2 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 .)