20. the main goal of extensible hypertext markup language (xhtml) is to
XHTML XHTML was developed to make HTML more extensible and increase interoperability with other data formats.[8] In addition, browsers were forgiving of errors in HTML, and most websites were displayed despite technical errors in the markup; XHTML introduced stricter error handling.[9] HTML 4 was ostensibly an application of Standard Generalized Markup Language (SGML); however the specification for SGML was complex, and neither web browsers nor the HTML 4 Recommendation were fully conformant to it.[10] The XML standard, approved in 1998, provided a simpler data format closer in simplicity to HTML 4.[11] By shifting to an XML format, it was hoped HTML would become compatible with common XML tools;[12] servers and proxies would be able to transform content, as necessary, for constrained devices such as mobile phones.[13] By using namespaces, XHTML documents could provide extensibility by including fragments from other XML-based languages such as Scalable Vector Graphics and MathML.[14] Finally, the renewed work would provide an opportunity to divide HTML into reusable components (XHTML Modularization) and clean up untidy parts of the language.[15]
Web server The primary function of a web server is to store, process and deliver web pages to clients. The communication between client and server takes place using the Hypertext Transfer Protocol (HTTP). Pages delivered are most frequently HTML documents, which may include images, style sheets and scripts in addition to the text content.