What is XML?

XML stands for Extensible Markup Language, it looks like HTML and is designed to describe the data. XML uses document type definition (DTD) or an XML schema to describe the data. In XML tags are not predefined and user has to define his/her own tags.

XML was developed by the SGML Editorial Board formed under the auspices of the World Wide Web Consortium (W3C) beginning in 1996. The design goals 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 shall be easy to write programs which process XML documents.
• The number of optional features in XML is to be kept to the absolute minimum, ideally zero.
• XML documents should be human-legible and reasonably clear.
• The XML design should be prepared quickly.
• The design of XML shall be formal and concise.
• XML documents shall be easy to create.
• Terseness in XML markup is of minimal importance.

Today XML is a W3C Recommendation. This means that XML has been reviewed and approved by the members of the W3C. XML is therefore deemed "stable" and ready for widespread deployment. A Recommendation is the highest level a W3C document can be assigned. XML became a Recommendation on February 10, 1998.

Main Difference between XML and HTML:

The following link shows and example of an XML document.

 http://www.geocities.com/sia_irfan/DatabaseApplicationForManagers/Student.xml

References:  http://www.idealliance.org,  http://www.w3schools.com