HTML stands for Hyper Text Markup Language. It is used for create web pages. It is written in the form of HTML essentials consisting of tags with these angle brackets like <html>.It is a reformulation of HTML 4.01 in XML: Unlike HTML, which means SGML, was defined using the XHTML strict and easier to parse SGML subset of XML as a language basis. XHTML documents thus satisfy the syntax rules of XML.
XHTML 1.0: The transition from HTML to XHTML
XHTML 1.0 includes all elements of HTML 4.01, so a conversion of HTML 4.01 compliant pages to XHTML 1.0 is easily possible. A non-XHTML-compliant web browser can XHTML documents under certain conditions still represent correctly (see MIME Types and HTML compatibility): it processes them as normal HTML. This exploits that the HTML parser used browsers tolerant of syntax errors are. This fault-tolerance arose as a response to numerous HTML documents on the World Wide Web did not meet the formal standard, and users perceive browser messages about HTML syntax error as a nuisance. For XHTML, however, the basic idea of XML is considered uncomplicated exchange of data and the ease of automated processing. Therefore, programs that process the XHTML, no longer such a tolerant.
Recent XHTML document types contain no layout Awards more. XHTML Transitional 1.0 is the last document type, which still contains layout elements, such as <font> and <b>. In more modern types of documents as XHTML Strict 1.0 although few layout elements are still present, but only for backward compatibility with the Transitional – document type. In XHTML Basic or XHTML 2 finally layout elements are no longer included. For the visual design of XHTML elements should only external CSS rules are
In order to enable the development of languages ??based on XHTML, related and related items in XHTML 1.1 were summarized in so-called modules. Based on these in DTDs and in the future in XML schema documents drawn modules can create your own XHTML document types the modular principle and mix with other XML-based languages. Example applications of XHTML Modularization are XHTML 1.1, XHTML Basic and the mixtures with SMIL (multimedia), SVG (vector graphics) and MathML (mathematical formula set). For integration of general objects such as multimedia plug-ins, there is the object module.