XML, a Simple and Flexible Text Format
XML or Extensible Markup Language is a simple and very flexible text format developed from SGML. XML was originally created to store and transport data and to meet the challenges of electronic publishing. Currently, XML is playing an increasingly significant role in exchanging a large variety of data on the Internet.
XML is human and machine-readable and self-descriptive format with the embedded data structure. XML differs from HTML because they were designed for different goals. XML focuses on what data is while HTML focuses on how data looks. Unlike HTML, XML has no predefined tags but it provides a facility to explain and describe tags and the structural relationships between them. All tags in an XML document are defined by its author. XML is extensible so most XML applications will continue to work even when new data is added to the document or removed from it.
XML makes it possible to store, share, and transport data in a software- and hardware-independent way because it stores all data in a plain text format and there is no need to worry about compatibility when exchanging data or upgrading operating systems.
XML is used in different aspects of web development. Since XML doesn't provide any information on how data should be displayed, the same data can be used in a lot of different presentations. Very often XML is used in different HTML applications to store and transport data and HTML is used to format and present the same data. With XML, data can be stored in separate XML files so while displaying data in HTML, there is no need to edit the HTML file when data is changed.
XML formally describes different data and uses Document Type Definition to do it. There are thousands of XML formats that exist in different industries and used to describe data transactions, for example, medical data, news information, financial transactions, scientific measurements, and more.