As web developers know very well, basic HTML (HyperText Markup Language) offers no structure to web pages and format the content is mixed. Allow web pages to be structured for automated processing (eg electronic commerce), developed by the World Wide Web Consortium (W3C), an improved HTML. The result was two new languages, was an XSL (Extensible Style Language) and XML (eXtensible Markup Language), a system for defining, validating and sharing document formats on the web. XML is best known for the many bloggers and netizens as RSS (Rich Site Summary / Really Simple Syndication), which actually is an easy XML format used to share news and blog updates. History W3C, an organization dedicated to the development of the Web and the standardization of protocols, formed a working group on XML is led by Jon Bosak, Sun Microsystems 1996th Several major industry players have also been included in the Working Group is Adobe, Hewlett-Packard, Microsoft, Netscape, and Fuji Xerox. The group has published a Working Draft for XML in November of that year. Two years later, has announced the release of the W3C XML 1st 0 specification. In 1999 found the release of two W3C XML recommendations. Namespaces in XML first one had the right, and the other was Associating Style Sheets with XML documents. In January 2001 the Internet Engineering Task Force (IETF) published a draft standard XML media types. Profile XML is an open, readable text format derived from the rules Generalized Markup Language (SGML). The original purpose of large-scale electronic publishing, XML is now used for the exchange of different types of data on the Web and elsewhere. It becomes a language choice for communication between application programs. Design objectives XML Working Group (taken from the home page for the W3C) for XML are: XML shall be straightforwardly usable over the Internet. XML shall support a wide variety of applications. XML shall be compatible with SGML. It will be easy to write programs which process XML documents. The number of optional features in XML is to be kept to an absolute minimum, ideally zero. XML documents should be human readable and reasonably clear. XML design should be prepared quickly. The design of XML shall be formal and concise. XML documents shall be easy to create. Concise in XML is of minor importance. It describes the markup language of XML documents, which are a class of data objects. In addition, XML also describes the behavior of software modules called XML processors. These are used to read XML documents and provide access to its content and structure. Syntax HTML sufficiently familiar with XML syntax is very similar. However, it assumes that coding in XML is easy with no pain – XML is stricter than HTML, and sloppy HTML coders do well to remember it. Several reminders to code in XML: All items must have a closing tag. All items must be properly nested. All tags are case-sensitive. All attribute values must be quoted. A good hands-on tutorial on XML can be found at W3Schools. com.