Introduction to XML and AJAX
Basics of XML
XML, which stands for eXtensible Markup Language is a general-purpose specification for creating custom markup languages. It is classified as an extensible language, because it allows the user to define the mark-up elements. XML’s purpose is to aid information systems in sharing semi-structured data, especially via the Internet, to encode documents, and to serialize data.
XML is a markup language much like HTML. But they serve different purposes. HTML was designed to format and display data, with focus on how data looks. Whereas XML was designed to store and transport data, not to display data. Therefore HTML is about displaying information, while XML is about carrying information.
XML tags are not predefined. We must define our own tags. XML is designed to be self-descriptive and is recommended by World Wide Web Consortium (W3C). XML is just plain text. Software that can handle plain text can also handle XML. However, XML-aware applications can handle the XML tags specially. The functional meaning of the tags depends on the nature of the application.
Features of XML :
- XML is a markup language and its tags are user-defined.
- XML is recommended by W3C and it is designed to be self-descriptive.
- XML is not a replacement for HTML. Rather, it is a complement to HTML.
- XML was designed to store and transport data, with focus on carrying information.
Basics of AJAX
AJAX is based on the following web standards :
The web standards used in AJAX are well-defined, and supported by all major browsers. AJAX applications are browser and platform independent.
Φ We start with XML here followed by AJAX.