XML

	What are XML parsers? XML Parser is a interface between user and XML Document. XML Parsers are divided into 2 types 1) DOM (Document Object Module) 2) SAX (Simple API for XML)
	What does "XML" stand for? "Extensible Markup Language." The name emphasizes the key feature of the language as it will be seen by an HTML user - the ability to define your own tags and attributes, which, of course, HTML does not allow.
	What is the difference between Schema and DTD? DTD can have only two types of data, the CDATA and the PCDATA. But in a schema you can use all the primitive data type that you use in the programming language and you have the flexibility of defining your own custom data types. The developer building a schema can create custom data types based on the core data types and by using different operators and modifiers. Object orientation support is there in a schema and hence encapsulation and inheritance are there in using a schema. If you use schema then support for web services, XSLT, and other XML based technologies are there for your XML applications. Data types like integer, string, floating point numbers and other data like country codes and language codes can be used in a schema to give flexibility to the validations.
	What is XML Namespace? XML namespaces are used for providing uniquely named elements and attributes in an XML document. They are defined in Namespaces in XML, a W3C recommendation. An XML instance may contain element or attribute names from more than one XML vocabulary. If each vocabulary is given a namespace then the ambiguity between identically named elements or attributes can be resolved. A simple example would be to consider an XML instance that contained references to a customer and an ordered product. Both the customer element and the product element could have a child element named id. References to the id element would therefore be ambiguous; placing them in different namespaces would remove the ambiguity
	What is Xpath? XPath is a language that describes how to locate specific elements (and attributes, processing instructions, etc.) in a document. It allows you to locate specific content within an XML document. XPATH treats an XML document as a logical ordered tree,
	What is XSL? XSL is a language for expressing style sheets. An XSL style sheet is, like with CSS, a file that describes how to display an XML document of a given type. XSL shares the functionality and is compatible with CSS2 (although it uses a different syntax). It also adds: * A transformation language for XML documents: XSLT. Originally intended to perform complex styling operations, like the generation of tables of contents and indexes, it is now used as a general purpose XML processing language. XSLT is thus widely used for purposes other than XSL, like generating HTML web pages from XML data. * Advanced styling features, expressed by an XML document type which defines a set of elements called Formatting Objects, and attributes (in part borrowed from CSS2 properties and adding more complex ones.
	What is XSLT? XSLT (XSL Transformations) is a declarative, XML-based language used for the transformation of XML documents into other XML documents. The original document is not changed; rather, a new document is created based on the content of an existing one.[2] The new document may be serialized (output) by the processor in standard XML syntax or in another format, such as HTML or plain text.[3] XSLT is often used to convert XML data into HTML or XHTML documents for display as a web page: the transformation may happen dynamically either on the client or on the server, or it may be done as part of the publishing process. It is also used to create output for printing or direct video display, typically by transforming the original XML into XSL Formatting Objects to create formatted output which can then be converted to a variety of formats, a few of which are PDF, PostScript, AWT and PNG. XSLT is also used to translate XML messages between different XML schemas, or to make changes to documents within the scope of a single schema, for example by removing the parts of a message that are not needed.