About XML

XML

A Document Type Definition (DTD) defines the legal building blocks of an XML document. It defines rules for a specific type of document, including:

• Names of elements, and how and where they can be used
• The order of elements
• Proper nesting and containment of elements
• Element attributes

To apply a DTD to an XML document, you can:

• Include the DTD's element definitions within the XML document itself.
• Provide the DTD as a separate file, whose name you reference in the XML document.

An XML Schema describes the structure of an XML instance document by defining what each element must or may contain.XML Schema is expressed in the form of a separate XML file.

CDATA Sections are used to escape blocks of text containing characters which would otherwise be recognized as markup. All tags and entity references are ignored by an XML processor that treats them just like any character data. CDATA blocks have been provided as a convenience measure when you want to include large blocks of special characters as character data, but you do not want to have to use entity references all the time.


eXtensible Stylesheet Language(XSL)  deals with most displaying the contents of XML documents.XSL consists of three parts: