2. eXtensible Markup Language
Became a W3C recommendation in 1998
Subset of SGML (Standard Generalized Markup
Language)
Describes a class of data objects called XML documents
Metalanguage (language for describing other
languages)
Tags are not predefined, designed to be self-prescriptive
“XML is a software- and hardware-dependent tool for
carrying information.”4
3. The goal of XML: Why?
To enable generic SGML to be Browsers never allowed
served, received, and SGML
processed on the Web in a
way that is not possible with HTML is easy to corrupt or
break
HTML. XML has been designed
to operate with both SGML Widespread
and HTML. Held back
development
XML fixes that by creating
compulsory rules
4. The Basics
XML documents consist entirely of characters from
Unicode (not all Unicode characters are included).
Characters that make up XML are divided into markup
and content.
Unicode character sets are encoded into bytes for
storage or transmission.
The processor analyses the markup and passes structured
information to an application.
5. XML Document
Begins with XML declaration and document type
declaration
Followed by Document Instance, containing root
element (start/end tags) and elements enclosing the
data content (text) and any attributes („name=“value”‟
pairs)
Documents can be simple, with straightforward nested
markup, or more complicated with Schema or DTD
(describe structure of the document)
6. Schema and DTD (Document Type Definition)
Define the allowed parts of an XML document:
The elements and attributes that can appear
Data types, default and fixed values
Identify child elements, and their order and number
Whether an element is empty or includes text
Schemas are the successors of DTDs
Extensible to future additions, richer and more
powerful, support data types and namespaces, written in
XML
XML Schema became a W3C recommendation in 2001
7. Stylesheets (CSS and XMLT)
Transform XML into HTML
Allow for document management benefits of XML, but
readers don‟t need XML smarts in their browsers
XMLT is an document processing language that uses XML
source code
Declares rules for processor to use when interpreting XML
document
8. Browsers
Current versions of Internet Explorer, Firefox, Safari,
Chrome, and Opera all support XML with CSS or
XSLT stylesheets.
Does not work with any versions of Netscape, IE
6.0 or earlier, or early versions of Mozilla.
9. The Difference
XML HMTL
Designed to transport and Designed to display data
store data
Focuses on how data looks
Focuses on what data is
XHTML is “a reformulation of HTML 4 in XML
1.0”
10. HTML5
Intended to include HTML and XHTML
XHTML5 is an XML serialization of HTML5, meaning the
data structure or object state is converted into a form
that can be stored.